diff --git a/crates/call/src/room.rs b/crates/call/src/room.rs
index b26a8fcbfe..1d22fe50f1 100644
--- a/crates/call/src/room.rs
+++ b/crates/call/src/room.rs
@@ -3,7 +3,7 @@ use crate::{
     IncomingCall,
 };
 use anyhow::{anyhow, Result};
-use client::{proto, Client, PeerId, TypedEnvelope, User, UserStore};
+use client::{proto, Client, TypedEnvelope, User, UserStore};
 use collections::{BTreeMap, HashSet};
 use futures::{FutureExt, StreamExt};
 use gpui::{
@@ -20,10 +20,10 @@ pub const RECONNECT_TIMEOUT: Duration = client::RECEIVE_TIMEOUT;
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum Event {
     ParticipantLocationChanged {
-        participant_id: PeerId,
+        participant_id: proto::PeerId,
     },
     RemoteVideoTracksChanged {
-        participant_id: PeerId,
+        participant_id: proto::PeerId,
     },
     RemoteProjectShared {
         owner: Arc<User>,
@@ -41,7 +41,7 @@ pub struct Room {
     live_kit: Option<LiveKitRoom>,
     status: RoomStatus,
     local_participant: LocalParticipant,
-    remote_participants: BTreeMap<PeerId, RemoteParticipant>,
+    remote_participants: BTreeMap<proto::PeerId, RemoteParticipant>,
     pending_participants: Vec<Arc<User>>,
     participant_user_ids: HashSet<u64>,
     pending_call_count: usize,
@@ -349,7 +349,7 @@ impl Room {
         &self.local_participant
     }
 
-    pub fn remote_participants(&self) -> &BTreeMap<PeerId, RemoteParticipant> {
+    pub fn remote_participants(&self) -> &BTreeMap<proto::PeerId, RemoteParticipant> {
         &self.remote_participants
     }
 
@@ -419,7 +419,7 @@ impl Room {
                 if let Some(participants) = remote_participants.log_err() {
                     let mut participant_peer_ids = HashSet::default();
                     for (participant, user) in room.participants.into_iter().zip(participants) {
-                        let peer_id = PeerId(participant.peer_id);
+                        let Some(peer_id) = participant.peer_id else { continue };
                         this.participant_user_ids.insert(participant.user_id);
                         participant_peer_ids.insert(peer_id);
 
@@ -476,7 +476,7 @@ impl Room {
 
                             if let Some(live_kit) = this.live_kit.as_ref() {
                                 let tracks =
-                                    live_kit.room.remote_video_tracks(&peer_id.0.to_string());
+                                    live_kit.room.remote_video_tracks(&peer_id.to_string());
                                 for track in tracks {
                                     this.remote_video_track_updated(
                                         RemoteVideoTrackUpdate::Subscribed(track),
@@ -531,7 +531,7 @@ impl Room {
     ) -> Result<()> {
         match change {
             RemoteVideoTrackUpdate::Subscribed(track) => {
-                let peer_id = PeerId(track.publisher_id().parse()?);
+                let peer_id = track.publisher_id().parse()?;
                 let track_id = track.sid().to_string();
                 let participant = self
                     .remote_participants
@@ -551,7 +551,7 @@ impl Room {
                 publisher_id,
                 track_id,
             } => {
-                let peer_id = PeerId(publisher_id.parse()?);
+                let peer_id = publisher_id.parse()?;
                 let participant = self
                     .remote_participants
                     .get_mut(&peer_id)
diff --git a/crates/client/src/client.rs b/crates/client/src/client.rs
index 5e10f9ea8f..876b83b11a 100644
--- a/crates/client/src/client.rs
+++ b/crates/client/src/client.rs
@@ -23,7 +23,7 @@ use lazy_static::lazy_static;
 use parking_lot::RwLock;
 use postage::watch;
 use rand::prelude::*;
-use rpc::proto::{AnyTypedEnvelope, EntityMessage, EnvelopedMessage, RequestMessage};
+use rpc::proto::{AnyTypedEnvelope, EntityMessage, EnvelopedMessage, PeerId, RequestMessage};
 use serde::Deserialize;
 use std::{
     any::TypeId,
@@ -140,7 +140,7 @@ impl EstablishConnectionError {
     }
 }
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub enum Status {
     SignedOut,
     UpgradeRequired,
@@ -306,7 +306,7 @@ impl Client {
     pub fn new(http: Arc<dyn HttpClient>, cx: &AppContext) -> Arc<Self> {
         Arc::new(Self {
             id: 0,
-            peer: Peer::new(),
+            peer: Peer::new(0),
             telemetry: Telemetry::new(http.clone(), cx),
             http,
             state: Default::default(),
@@ -810,7 +810,11 @@ impl Client {
                         hello_message_type_name
                     )
                 })?;
-            Ok(PeerId(hello.payload.peer_id))
+            let peer_id = hello
+                .payload
+                .peer_id
+                .ok_or_else(|| anyhow!("invalid peer id"))?;
+            Ok(peer_id)
         };
 
         let peer_id = match peer_id.await {
@@ -822,7 +826,7 @@ impl Client {
         };
 
         log::info!(
-            "set status to connected (connection id: {}, peer id: {})",
+            "set status to connected (connection id: {:?}, peer id: {:?})",
             connection_id,
             peer_id
         );
@@ -853,7 +857,7 @@ impl Client {
             .spawn(async move {
                 match handle_io.await {
                     Ok(()) => {
-                        if *this.status().borrow()
+                        if this.status().borrow().clone()
                             == (Status::Connected {
                                 connection_id,
                                 peer_id,
@@ -1194,7 +1198,7 @@ impl Client {
         let mut state = self.state.write();
         let type_name = message.payload_type_name();
         let payload_type_id = message.payload_type_id();
-        let sender_id = message.original_sender_id().map(|id| id.0);
+        let sender_id = message.original_sender_id();
 
         let mut subscriber = None;
 
diff --git a/crates/client/src/test.rs b/crates/client/src/test.rs
index 3cfba3b184..db9e0d8c48 100644
--- a/crates/client/src/test.rs
+++ b/crates/client/src/test.rs
@@ -35,7 +35,7 @@ impl FakeServer {
         cx: &TestAppContext,
     ) -> Self {
         let server = Self {
-            peer: Peer::new(),
+            peer: Peer::new(0),
             state: Default::default(),
             user_id: client_user_id,
             executor: cx.foreground(),
@@ -92,7 +92,7 @@ impl FakeServer {
                         peer.send(
                             connection_id,
                             proto::Hello {
-                                peer_id: connection_id.0,
+                                peer_id: Some(connection_id.into()),
                             },
                         )
                         .unwrap();
diff --git a/crates/collab/migrations.sqlite/20221109000000_test_schema.sql b/crates/collab/migrations.sqlite/20221109000000_test_schema.sql
index c0cc5b3457..b96b07d977 100644
--- a/crates/collab/migrations.sqlite/20221109000000_test_schema.sql
+++ b/crates/collab/migrations.sqlite/20221109000000_test_schema.sql
@@ -44,7 +44,7 @@ CREATE TABLE "projects" (
     "room_id" INTEGER REFERENCES rooms (id) NOT NULL,
     "host_user_id" INTEGER REFERENCES users (id) NOT NULL,
     "host_connection_id" INTEGER NOT NULL,
-    "host_connection_epoch" TEXT NOT NULL,
+    "host_connection_epoch" INTEGER NOT NULL,
     "unregistered" BOOLEAN NOT NULL DEFAULT FALSE
 );
 CREATE INDEX "index_projects_on_host_connection_epoch" ON "projects" ("host_connection_epoch");
@@ -103,7 +103,7 @@ CREATE TABLE "project_collaborators" (
     "id" INTEGER PRIMARY KEY AUTOINCREMENT,
     "project_id" INTEGER NOT NULL REFERENCES projects (id) ON DELETE CASCADE,
     "connection_id" INTEGER NOT NULL,
-    "connection_epoch" TEXT NOT NULL,
+    "connection_epoch" INTEGER NOT NULL,
     "user_id" INTEGER NOT NULL,
     "replica_id" INTEGER NOT NULL,
     "is_host" BOOLEAN NOT NULL
@@ -119,14 +119,14 @@ CREATE TABLE "room_participants" (
     "room_id" INTEGER NOT NULL REFERENCES rooms (id),
     "user_id" INTEGER NOT NULL REFERENCES users (id),
     "answering_connection_id" INTEGER,
-    "answering_connection_epoch" TEXT,
+    "answering_connection_epoch" INTEGER,
     "answering_connection_lost" BOOLEAN NOT NULL,
     "location_kind" INTEGER,
     "location_project_id" INTEGER,
     "initial_project_id" INTEGER,
     "calling_user_id" INTEGER NOT NULL REFERENCES users (id),
     "calling_connection_id" INTEGER NOT NULL,
-    "calling_connection_epoch" TEXT NOT NULL
+    "calling_connection_epoch" INTEGER NOT NULL
 );
 CREATE UNIQUE INDEX "index_room_participants_on_user_id" ON "room_participants" ("user_id");
 CREATE INDEX "index_room_participants_on_room_id" ON "room_participants" ("room_id");
diff --git a/crates/collab/migrations/20221214144346_change_epoch_from_uuid_to_integer.sql b/crates/collab/migrations/20221214144346_change_epoch_from_uuid_to_integer.sql
new file mode 100644
index 0000000000..ed294502a5
--- /dev/null
+++ b/crates/collab/migrations/20221214144346_change_epoch_from_uuid_to_integer.sql
@@ -0,0 +1,9 @@
+ALTER TABLE "projects"
+    ALTER COLUMN "host_connection_epoch" TYPE INTEGER USING 0;
+
+ALTER TABLE "project_collaborators"
+    ALTER COLUMN "connection_epoch" TYPE INTEGER USING 0;
+
+ALTER TABLE "room_participants"
+    ALTER COLUMN "answering_connection_epoch" TYPE INTEGER USING 0,
+    ALTER COLUMN "calling_connection_epoch" TYPE INTEGER USING 0;
diff --git a/crates/collab/src/db.rs b/crates/collab/src/db.rs
index 892ea4ccd6..6237cc4f79 100644
--- a/crates/collab/src/db.rs
+++ b/crates/collab/src/db.rs
@@ -1076,7 +1076,7 @@ impl Database {
     pub async fn create_room(
         &self,
         user_id: UserId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
         live_kit_room: &str,
     ) -> Result<RoomGuard<proto::Room>> {
         self.room_transaction(|tx| async move {
@@ -1091,12 +1091,12 @@ impl Database {
             room_participant::ActiveModel {
                 room_id: ActiveValue::set(room_id),
                 user_id: ActiveValue::set(user_id),
-                answering_connection_id: ActiveValue::set(Some(connection_id.0 as i32)),
-                answering_connection_epoch: ActiveValue::set(Some(self.epoch())),
+                answering_connection_id: ActiveValue::set(Some(connection.id as i32)),
+                answering_connection_epoch: ActiveValue::set(Some(connection.epoch as i32)),
                 answering_connection_lost: ActiveValue::set(false),
                 calling_user_id: ActiveValue::set(user_id),
-                calling_connection_id: ActiveValue::set(connection_id.0 as i32),
-                calling_connection_epoch: ActiveValue::set(self.epoch()),
+                calling_connection_id: ActiveValue::set(connection.id as i32),
+                calling_connection_epoch: ActiveValue::set(connection.epoch as i32),
                 ..Default::default()
             }
             .insert(&*tx)
@@ -1112,7 +1112,7 @@ impl Database {
         &self,
         room_id: RoomId,
         calling_user_id: UserId,
-        calling_connection_id: ConnectionId,
+        calling_connection: ConnectionId,
         called_user_id: UserId,
         initial_project_id: Option<ProjectId>,
     ) -> Result<RoomGuard<(proto::Room, proto::IncomingCall)>> {
@@ -1122,8 +1122,8 @@ impl Database {
                 user_id: ActiveValue::set(called_user_id),
                 answering_connection_lost: ActiveValue::set(false),
                 calling_user_id: ActiveValue::set(calling_user_id),
-                calling_connection_id: ActiveValue::set(calling_connection_id.0 as i32),
-                calling_connection_epoch: ActiveValue::set(self.epoch()),
+                calling_connection_id: ActiveValue::set(calling_connection.id as i32),
+                calling_connection_epoch: ActiveValue::set(calling_connection.epoch as i32),
                 initial_project_id: ActiveValue::set(initial_project_id),
                 ..Default::default()
             }
@@ -1192,19 +1192,23 @@ impl Database {
     pub async fn cancel_call(
         &self,
         expected_room_id: Option<RoomId>,
-        calling_connection_id: ConnectionId,
+        calling_connection: ConnectionId,
         called_user_id: UserId,
     ) -> Result<RoomGuard<proto::Room>> {
         self.room_transaction(|tx| async move {
             let participant = room_participant::Entity::find()
                 .filter(
-                    room_participant::Column::UserId
-                        .eq(called_user_id)
-                        .and(
+                    Condition::all()
+                        .add(room_participant::Column::UserId.eq(called_user_id))
+                        .add(
                             room_participant::Column::CallingConnectionId
-                                .eq(calling_connection_id.0 as i32),
+                                .eq(calling_connection.id as i32),
                         )
-                        .and(room_participant::Column::AnsweringConnectionId.is_null()),
+                        .add(
+                            room_participant::Column::CallingConnectionEpoch
+                                .eq(calling_connection.epoch as i32),
+                        )
+                        .add(room_participant::Column::AnsweringConnectionId.is_null()),
                 )
                 .one(&*tx)
                 .await?
@@ -1228,7 +1232,7 @@ impl Database {
         &self,
         room_id: RoomId,
         user_id: UserId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<proto::Room>> {
         self.room_transaction(|tx| async move {
             let result = room_participant::Entity::update_many()
@@ -1242,13 +1246,13 @@ impl Database {
                                 .add(room_participant::Column::AnsweringConnectionLost.eq(true))
                                 .add(
                                     room_participant::Column::AnsweringConnectionEpoch
-                                        .ne(self.epoch()),
+                                        .ne(connection.epoch as i32),
                                 ),
                         ),
                 )
                 .set(room_participant::ActiveModel {
-                    answering_connection_id: ActiveValue::set(Some(connection_id.0 as i32)),
-                    answering_connection_epoch: ActiveValue::set(Some(self.epoch())),
+                    answering_connection_id: ActiveValue::set(Some(connection.id as i32)),
+                    answering_connection_epoch: ActiveValue::set(Some(connection.epoch as i32)),
                     answering_connection_lost: ActiveValue::set(false),
                     ..Default::default()
                 })
@@ -1264,10 +1268,20 @@ impl Database {
         .await
     }
 
-    pub async fn leave_room(&self, connection_id: ConnectionId) -> Result<RoomGuard<LeftRoom>> {
+    pub async fn leave_room(&self, connection: ConnectionId) -> Result<RoomGuard<LeftRoom>> {
         self.room_transaction(|tx| async move {
             let leaving_participant = room_participant::Entity::find()
-                .filter(room_participant::Column::AnsweringConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(
+                            room_participant::Column::AnsweringConnectionId
+                                .eq(connection.id as i32),
+                        )
+                        .add(
+                            room_participant::Column::AnsweringConnectionEpoch
+                                .eq(connection.epoch as i32),
+                        ),
+                )
                 .one(&*tx)
                 .await?;
 
@@ -1281,9 +1295,16 @@ impl Database {
                 // Cancel pending calls initiated by the leaving user.
                 let called_participants = room_participant::Entity::find()
                     .filter(
-                        room_participant::Column::CallingConnectionId
-                            .eq(connection_id.0)
-                            .and(room_participant::Column::AnsweringConnectionId.is_null()),
+                        Condition::all()
+                            .add(
+                                room_participant::Column::CallingConnectionId
+                                    .eq(connection.id as i32),
+                            )
+                            .add(
+                                room_participant::Column::CallingConnectionEpoch
+                                    .eq(connection.epoch as i32),
+                            )
+                            .add(room_participant::Column::AnsweringConnectionId.is_null()),
                     )
                     .all(&*tx)
                     .await?;
@@ -1310,7 +1331,16 @@ impl Database {
                         project_collaborator::Column::ProjectId,
                         QueryProjectIds::ProjectId,
                     )
-                    .filter(project_collaborator::Column::ConnectionId.eq(connection_id.0 as i32))
+                    .filter(
+                        Condition::all()
+                            .add(
+                                project_collaborator::Column::ConnectionId.eq(connection.id as i32),
+                            )
+                            .add(
+                                project_collaborator::Column::ConnectionEpoch
+                                    .eq(connection.epoch as i32),
+                            ),
+                    )
                     .into_values::<_, QueryProjectIds>()
                     .all(&*tx)
                     .await?;
@@ -1331,32 +1361,43 @@ impl Database {
                                 host_connection_id: Default::default(),
                             });
 
-                    let collaborator_connection_id =
-                        ConnectionId(collaborator.connection_id as u32);
-                    if collaborator_connection_id != connection_id {
+                    let collaborator_connection_id = ConnectionId {
+                        epoch: collaborator.connection_epoch as u32,
+                        id: collaborator.connection_id as u32,
+                    };
+                    if collaborator_connection_id != connection {
                         left_project.connection_ids.push(collaborator_connection_id);
                     }
 
                     if collaborator.is_host {
                         left_project.host_user_id = collaborator.user_id;
-                        left_project.host_connection_id =
-                            ConnectionId(collaborator.connection_id as u32);
+                        left_project.host_connection_id = collaborator_connection_id;
                     }
                 }
                 drop(collaborators);
 
                 // Leave projects.
                 project_collaborator::Entity::delete_many()
-                    .filter(project_collaborator::Column::ConnectionId.eq(connection_id.0 as i32))
+                    .filter(
+                        Condition::all()
+                            .add(
+                                project_collaborator::Column::ConnectionId.eq(connection.id as i32),
+                            )
+                            .add(
+                                project_collaborator::Column::ConnectionEpoch
+                                    .eq(connection.epoch as i32),
+                            ),
+                    )
                     .exec(&*tx)
                     .await?;
 
                 // Unshare projects.
                 project::Entity::delete_many()
                     .filter(
-                        project::Column::RoomId
-                            .eq(room_id)
-                            .and(project::Column::HostConnectionId.eq(connection_id.0 as i32)),
+                        Condition::all()
+                            .add(project::Column::RoomId.eq(room_id))
+                            .add(project::Column::HostConnectionId.eq(connection.id as i32))
+                            .add(project::Column::HostConnectionEpoch.eq(connection.epoch as i32)),
                     )
                     .exec(&*tx)
                     .await?;
@@ -1387,7 +1428,7 @@ impl Database {
     pub async fn update_room_participant_location(
         &self,
         room_id: RoomId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
         location: proto::ParticipantLocation,
     ) -> Result<RoomGuard<proto::Room>> {
         self.room_transaction(|tx| async {
@@ -1414,9 +1455,18 @@ impl Database {
             }
 
             let result = room_participant::Entity::update_many()
-                .filter(room_participant::Column::RoomId.eq(room_id).and(
-                    room_participant::Column::AnsweringConnectionId.eq(connection_id.0 as i32),
-                ))
+                .filter(
+                    Condition::all()
+                        .add(room_participant::Column::RoomId.eq(room_id))
+                        .add(
+                            room_participant::Column::AnsweringConnectionId
+                                .eq(connection.id as i32),
+                        )
+                        .add(
+                            room_participant::Column::AnsweringConnectionEpoch
+                                .eq(connection.epoch as i32),
+                        ),
+                )
                 .set(room_participant::ActiveModel {
                     location_kind: ActiveValue::set(Some(location_kind)),
                     location_project_id: ActiveValue::set(location_project_id),
@@ -1437,11 +1487,21 @@ impl Database {
 
     pub async fn connection_lost(
         &self,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<Vec<LeftProject>>> {
         self.room_transaction(|tx| async move {
             let participant = room_participant::Entity::find()
-                .filter(room_participant::Column::AnsweringConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(
+                            room_participant::Column::AnsweringConnectionId
+                                .eq(connection.id as i32),
+                        )
+                        .add(
+                            room_participant::Column::AnsweringConnectionEpoch
+                                .eq(connection.epoch as i32),
+                        ),
+                )
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("not a participant in any room"))?;
@@ -1456,11 +1516,25 @@ impl Database {
 
             let collaborator_on_projects = project_collaborator::Entity::find()
                 .find_also_related(project::Entity)
-                .filter(project_collaborator::Column::ConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(project_collaborator::Column::ConnectionId.eq(connection.id as i32))
+                        .add(
+                            project_collaborator::Column::ConnectionEpoch
+                                .eq(connection.epoch as i32),
+                        ),
+                )
                 .all(&*tx)
                 .await?;
             project_collaborator::Entity::delete_many()
-                .filter(project_collaborator::Column::ConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(project_collaborator::Column::ConnectionId.eq(connection.id as i32))
+                        .add(
+                            project_collaborator::Column::ConnectionEpoch
+                                .eq(connection.epoch as i32),
+                        ),
+                )
                 .exec(&*tx)
                 .await?;
 
@@ -1473,20 +1547,30 @@ impl Database {
                         .await?;
                     let connection_ids = collaborators
                         .into_iter()
-                        .map(|collaborator| ConnectionId(collaborator.connection_id as u32))
+                        .map(|collaborator| ConnectionId {
+                            id: collaborator.connection_id as u32,
+                            epoch: collaborator.connection_epoch as u32,
+                        })
                         .collect();
 
                     left_projects.push(LeftProject {
                         id: project.id,
                         host_user_id: project.host_user_id,
-                        host_connection_id: ConnectionId(project.host_connection_id as u32),
+                        host_connection_id: ConnectionId {
+                            id: project.host_connection_id as u32,
+                            epoch: project.host_connection_epoch as u32,
+                        },
                         connection_ids,
                     });
                 }
             }
 
             project::Entity::delete_many()
-                .filter(project::Column::HostConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(project::Column::HostConnectionId.eq(connection.id as i32))
+                        .add(project::Column::HostConnectionEpoch.eq(connection.epoch as i32)),
+                )
                 .exec(&*tx)
                 .await?;
 
@@ -1537,7 +1621,10 @@ impl Database {
         let mut pending_participants = Vec::new();
         while let Some(db_participant) = db_participants.next().await {
             let db_participant = db_participant?;
-            if let Some(answering_connection_id) = db_participant.answering_connection_id {
+            if let Some((answering_connection_id, answering_connection_epoch)) = db_participant
+                .answering_connection_id
+                .zip(db_participant.answering_connection_epoch)
+            {
                 let location = match (
                     db_participant.location_kind,
                     db_participant.location_project_id,
@@ -1560,7 +1647,10 @@ impl Database {
                     answering_connection_id,
                     proto::Participant {
                         user_id: db_participant.user_id.to_proto(),
-                        peer_id: answering_connection_id as u32,
+                        peer_id: Some(proto::PeerId {
+                            epoch: answering_connection_epoch as u32,
+                            id: answering_connection_id as u32,
+                        }),
                         projects: Default::default(),
                         location: Some(proto::ParticipantLocation { variant: location }),
                     },
@@ -1637,12 +1727,22 @@ impl Database {
     pub async fn share_project(
         &self,
         room_id: RoomId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
         worktrees: &[proto::WorktreeMetadata],
     ) -> Result<RoomGuard<(ProjectId, proto::Room)>> {
         self.room_transaction(|tx| async move {
             let participant = room_participant::Entity::find()
-                .filter(room_participant::Column::AnsweringConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(
+                            room_participant::Column::AnsweringConnectionId
+                                .eq(connection.id as i32),
+                        )
+                        .add(
+                            room_participant::Column::AnsweringConnectionEpoch
+                                .eq(connection.epoch as i32),
+                        ),
+                )
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("could not find participant"))?;
@@ -1653,8 +1753,8 @@ impl Database {
             let project = project::ActiveModel {
                 room_id: ActiveValue::set(participant.room_id),
                 host_user_id: ActiveValue::set(participant.user_id),
-                host_connection_id: ActiveValue::set(connection_id.0 as i32),
-                host_connection_epoch: ActiveValue::set(self.epoch()),
+                host_connection_id: ActiveValue::set(connection.id as i32),
+                host_connection_epoch: ActiveValue::set(connection.epoch as i32),
                 ..Default::default()
             }
             .insert(&*tx)
@@ -1678,8 +1778,8 @@ impl Database {
 
             project_collaborator::ActiveModel {
                 project_id: ActiveValue::set(project.id),
-                connection_id: ActiveValue::set(connection_id.0 as i32),
-                connection_epoch: ActiveValue::set(self.epoch()),
+                connection_id: ActiveValue::set(connection.id as i32),
+                connection_epoch: ActiveValue::set(connection.epoch as i32),
                 user_id: ActiveValue::set(participant.user_id),
                 replica_id: ActiveValue::set(ReplicaId(0)),
                 is_host: ActiveValue::set(true),
@@ -1697,7 +1797,7 @@ impl Database {
     pub async fn unshare_project(
         &self,
         project_id: ProjectId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<(proto::Room, Vec<ConnectionId>)>> {
         self.room_transaction(|tx| async move {
             let guest_connection_ids = self.project_guest_connection_ids(project_id, &tx).await?;
@@ -1706,7 +1806,11 @@ impl Database {
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("project not found"))?;
-            if project.host_connection_id == connection_id.0 as i32 {
+            let host_connection = ConnectionId {
+                epoch: project.host_connection_epoch as u32,
+                id: project.host_connection_id as u32,
+            };
+            if host_connection == connection {
                 let room_id = project.room_id;
                 project::Entity::delete(project.into_active_model())
                     .exec(&*tx)
@@ -1723,12 +1827,16 @@ impl Database {
     pub async fn update_project(
         &self,
         project_id: ProjectId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
         worktrees: &[proto::WorktreeMetadata],
     ) -> Result<RoomGuard<(proto::Room, Vec<ConnectionId>)>> {
         self.room_transaction(|tx| async move {
             let project = project::Entity::find_by_id(project_id)
-                .filter(project::Column::HostConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(project::Column::HostConnectionId.eq(connection.id as i32))
+                        .add(project::Column::HostConnectionEpoch.eq(connection.epoch as i32)),
+                )
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("no such project"))?;
@@ -1774,7 +1882,7 @@ impl Database {
     pub async fn update_worktree(
         &self,
         update: &proto::UpdateWorktree,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<Vec<ConnectionId>>> {
         self.room_transaction(|tx| async move {
             let project_id = ProjectId::from_proto(update.project_id);
@@ -1782,7 +1890,11 @@ impl Database {
 
             // Ensure the update comes from the host.
             let project = project::Entity::find_by_id(project_id)
-                .filter(project::Column::HostConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(project::Column::HostConnectionId.eq(connection.id as i32))
+                        .add(project::Column::HostConnectionEpoch.eq(connection.epoch as i32)),
+                )
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("no such project"))?;
@@ -1862,7 +1974,7 @@ impl Database {
     pub async fn update_diagnostic_summary(
         &self,
         update: &proto::UpdateDiagnosticSummary,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<Vec<ConnectionId>>> {
         self.room_transaction(|tx| async move {
             let project_id = ProjectId::from_proto(update.project_id);
@@ -1877,7 +1989,11 @@ impl Database {
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("no such project"))?;
-            if project.host_connection_id != connection_id.0 as i32 {
+            let host_connection = ConnectionId {
+                epoch: project.host_connection_epoch as u32,
+                id: project.host_connection_id as u32,
+            };
+            if host_connection != connection {
                 return Err(anyhow!("can't update a project hosted by someone else"))?;
             }
 
@@ -1916,7 +2032,7 @@ impl Database {
     pub async fn start_language_server(
         &self,
         update: &proto::StartLanguageServer,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<Vec<ConnectionId>>> {
         self.room_transaction(|tx| async move {
             let project_id = ProjectId::from_proto(update.project_id);
@@ -1930,7 +2046,11 @@ impl Database {
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("no such project"))?;
-            if project.host_connection_id != connection_id.0 as i32 {
+            let host_connection = ConnectionId {
+                epoch: project.host_connection_epoch as u32,
+                id: project.host_connection_id as u32,
+            };
+            if host_connection != connection {
                 return Err(anyhow!("can't update a project hosted by someone else"))?;
             }
 
@@ -1961,11 +2081,21 @@ impl Database {
     pub async fn join_project(
         &self,
         project_id: ProjectId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<(Project, ReplicaId)>> {
         self.room_transaction(|tx| async move {
             let participant = room_participant::Entity::find()
-                .filter(room_participant::Column::AnsweringConnectionId.eq(connection_id.0 as i32))
+                .filter(
+                    Condition::all()
+                        .add(
+                            room_participant::Column::AnsweringConnectionId
+                                .eq(connection.id as i32),
+                        )
+                        .add(
+                            room_participant::Column::AnsweringConnectionEpoch
+                                .eq(connection.epoch as i32),
+                        ),
+                )
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("must join a room first"))?;
@@ -1992,8 +2122,8 @@ impl Database {
             }
             let new_collaborator = project_collaborator::ActiveModel {
                 project_id: ActiveValue::set(project_id),
-                connection_id: ActiveValue::set(connection_id.0 as i32),
-                connection_epoch: ActiveValue::set(self.epoch()),
+                connection_id: ActiveValue::set(connection.id as i32),
+                connection_epoch: ActiveValue::set(connection.epoch as i32),
                 user_id: ActiveValue::set(participant.user_id),
                 replica_id: ActiveValue::set(replica_id),
                 is_host: ActiveValue::set(false),
@@ -2095,14 +2225,18 @@ impl Database {
     pub async fn leave_project(
         &self,
         project_id: ProjectId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<LeftProject>> {
         self.room_transaction(|tx| async move {
             let result = project_collaborator::Entity::delete_many()
                 .filter(
-                    project_collaborator::Column::ProjectId
-                        .eq(project_id)
-                        .and(project_collaborator::Column::ConnectionId.eq(connection_id.0 as i32)),
+                    Condition::all()
+                        .add(project_collaborator::Column::ProjectId.eq(project_id))
+                        .add(project_collaborator::Column::ConnectionId.eq(connection.id as i32))
+                        .add(
+                            project_collaborator::Column::ConnectionEpoch
+                                .eq(connection.epoch as i32),
+                        ),
                 )
                 .exec(&*tx)
                 .await?;
@@ -2120,13 +2254,19 @@ impl Database {
                 .await?;
             let connection_ids = collaborators
                 .into_iter()
-                .map(|collaborator| ConnectionId(collaborator.connection_id as u32))
+                .map(|collaborator| ConnectionId {
+                    epoch: collaborator.connection_epoch as u32,
+                    id: collaborator.connection_id as u32,
+                })
                 .collect();
 
             let left_project = LeftProject {
                 id: project_id,
                 host_user_id: project.host_user_id,
-                host_connection_id: ConnectionId(project.host_connection_id as u32),
+                host_connection_id: ConnectionId {
+                    epoch: project.host_connection_epoch as u32,
+                    id: project.host_connection_id as u32,
+                },
                 connection_ids,
             };
             Ok((project.room_id, left_project))
@@ -2137,7 +2277,7 @@ impl Database {
     pub async fn project_collaborators(
         &self,
         project_id: ProjectId,
-        connection_id: ConnectionId,
+        connection: ConnectionId,
     ) -> Result<RoomGuard<Vec<project_collaborator::Model>>> {
         self.room_transaction(|tx| async move {
             let project = project::Entity::find_by_id(project_id)
@@ -2149,10 +2289,13 @@ impl Database {
                 .all(&*tx)
                 .await?;
 
-            if collaborators
-                .iter()
-                .any(|collaborator| collaborator.connection_id == connection_id.0 as i32)
-            {
+            if collaborators.iter().any(|collaborator| {
+                let collaborator_connection = ConnectionId {
+                    epoch: collaborator.connection_epoch as u32,
+                    id: collaborator.connection_id as u32,
+                };
+                collaborator_connection == connection
+            }) {
                 Ok((project.room_id, collaborators))
             } else {
                 Err(anyhow!("no such project"))?
@@ -2166,30 +2309,42 @@ impl Database {
         project_id: ProjectId,
         connection_id: ConnectionId,
     ) -> Result<RoomGuard<HashSet<ConnectionId>>> {
-        self.room_transaction(|tx| async move {
-            #[derive(Copy, Clone, Debug, EnumIter, DeriveColumn)]
-            enum QueryAs {
-                ConnectionId,
-            }
+        #[derive(Copy, Clone, Debug, EnumIter, DeriveColumn)]
+        enum QueryAs {
+            Epoch,
+            Id,
+        }
 
+        #[derive(Debug, FromQueryResult)]
+        struct ProjectConnection {
+            epoch: i32,
+            id: i32,
+        }
+
+        self.room_transaction(|tx| async move {
             let project = project::Entity::find_by_id(project_id)
                 .one(&*tx)
                 .await?
                 .ok_or_else(|| anyhow!("no such project"))?;
-            let mut db_connection_ids = project_collaborator::Entity::find()
+            let mut db_connections = project_collaborator::Entity::find()
                 .select_only()
+                .column_as(project_collaborator::Column::ConnectionId, QueryAs::Id)
                 .column_as(
-                    project_collaborator::Column::ConnectionId,
-                    QueryAs::ConnectionId,
+                    project_collaborator::Column::ConnectionEpoch,
+                    QueryAs::Epoch,
                 )
                 .filter(project_collaborator::Column::ProjectId.eq(project_id))
-                .into_values::<i32, QueryAs>()
+                .into_model::<ProjectConnection>()
                 .stream(&*tx)
                 .await?;
 
             let mut connection_ids = HashSet::default();
-            while let Some(connection_id) = db_connection_ids.next().await {
-                connection_ids.insert(ConnectionId(connection_id? as u32));
+            while let Some(connection) = db_connections.next().await {
+                let connection = connection?;
+                connection_ids.insert(ConnectionId {
+                    epoch: connection.epoch as u32,
+                    id: connection.id as u32,
+                });
             }
 
             if connection_ids.contains(&connection_id) {
@@ -2208,27 +2363,39 @@ impl Database {
     ) -> Result<Vec<ConnectionId>> {
         #[derive(Copy, Clone, Debug, EnumIter, DeriveColumn)]
         enum QueryAs {
-            ConnectionId,
+            Epoch,
+            Id,
         }
 
-        let mut db_guest_connection_ids = project_collaborator::Entity::find()
+        #[derive(Debug, FromQueryResult)]
+        struct ProjectConnection {
+            epoch: i32,
+            id: i32,
+        }
+
+        let mut db_guest_connections = project_collaborator::Entity::find()
             .select_only()
+            .column_as(project_collaborator::Column::ConnectionId, QueryAs::Id)
             .column_as(
-                project_collaborator::Column::ConnectionId,
-                QueryAs::ConnectionId,
+                project_collaborator::Column::ConnectionEpoch,
+                QueryAs::Epoch,
             )
             .filter(
                 project_collaborator::Column::ProjectId
                     .eq(project_id)
                     .and(project_collaborator::Column::IsHost.eq(false)),
             )
-            .into_values::<i32, QueryAs>()
+            .into_model::<ProjectConnection>()
             .stream(tx)
             .await?;
 
         let mut guest_connection_ids = Vec::new();
-        while let Some(connection_id) = db_guest_connection_ids.next().await {
-            guest_connection_ids.push(ConnectionId(connection_id? as u32));
+        while let Some(connection) = db_guest_connections.next().await {
+            let connection = connection?;
+            guest_connection_ids.push(ConnectionId {
+                epoch: connection.epoch as u32,
+                id: connection.id as u32,
+            });
         }
         Ok(guest_connection_ids)
     }
diff --git a/crates/collab/src/db/project.rs b/crates/collab/src/db/project.rs
index 971a8fcefb..b8cf321e51 100644
--- a/crates/collab/src/db/project.rs
+++ b/crates/collab/src/db/project.rs
@@ -9,7 +9,7 @@ pub struct Model {
     pub room_id: RoomId,
     pub host_user_id: UserId,
     pub host_connection_id: i32,
-    pub host_connection_epoch: Uuid,
+    pub host_connection_epoch: i32,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
diff --git a/crates/collab/src/db/project_collaborator.rs b/crates/collab/src/db/project_collaborator.rs
index 5db307f5df..e12b113ff9 100644
--- a/crates/collab/src/db/project_collaborator.rs
+++ b/crates/collab/src/db/project_collaborator.rs
@@ -8,7 +8,7 @@ pub struct Model {
     pub id: ProjectCollaboratorId,
     pub project_id: ProjectId,
     pub connection_id: i32,
-    pub connection_epoch: Uuid,
+    pub connection_epoch: i32,
     pub user_id: UserId,
     pub replica_id: ReplicaId,
     pub is_host: bool,
diff --git a/crates/collab/src/db/room_participant.rs b/crates/collab/src/db/room_participant.rs
index c80c10c1ba..265febd545 100644
--- a/crates/collab/src/db/room_participant.rs
+++ b/crates/collab/src/db/room_participant.rs
@@ -9,14 +9,14 @@ pub struct Model {
     pub room_id: RoomId,
     pub user_id: UserId,
     pub answering_connection_id: Option<i32>,
-    pub answering_connection_epoch: Option<Uuid>,
+    pub answering_connection_epoch: Option<i32>,
     pub answering_connection_lost: bool,
     pub location_kind: Option<i32>,
     pub location_project_id: Option<ProjectId>,
     pub initial_project_id: Option<ProjectId>,
     pub calling_user_id: UserId,
     pub calling_connection_id: i32,
-    pub calling_connection_epoch: Uuid,
+    pub calling_connection_epoch: i32,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
diff --git a/crates/collab/src/db/tests.rs b/crates/collab/src/db/tests.rs
index 2d254c2e37..b6b8a780a7 100644
--- a/crates/collab/src/db/tests.rs
+++ b/crates/collab/src/db/tests.rs
@@ -436,36 +436,44 @@ test_both_dbs!(
             .unwrap();
 
         let room_id = RoomId::from_proto(
-            db.create_room(user1.user_id, ConnectionId(0), "")
+            db.create_room(user1.user_id, ConnectionId { epoch: 0, id: 0 }, "")
                 .await
                 .unwrap()
                 .id,
         );
-        db.call(room_id, user1.user_id, ConnectionId(0), user2.user_id, None)
-            .await
-            .unwrap();
-        db.join_room(room_id, user2.user_id, ConnectionId(1))
+        db.call(
+            room_id,
+            user1.user_id,
+            ConnectionId { epoch: 0, id: 0 },
+            user2.user_id,
+            None,
+        )
+        .await
+        .unwrap();
+        db.join_room(room_id, user2.user_id, ConnectionId { epoch: 0, id: 1 })
             .await
             .unwrap();
         assert_eq!(db.project_count_excluding_admins().await.unwrap(), 0);
 
-        db.share_project(room_id, ConnectionId(1), &[])
+        db.share_project(room_id, ConnectionId { epoch: 0, id: 1 }, &[])
             .await
             .unwrap();
         assert_eq!(db.project_count_excluding_admins().await.unwrap(), 1);
 
-        db.share_project(room_id, ConnectionId(1), &[])
+        db.share_project(room_id, ConnectionId { epoch: 0, id: 1 }, &[])
             .await
             .unwrap();
         assert_eq!(db.project_count_excluding_admins().await.unwrap(), 2);
 
         // Projects shared by admins aren't counted.
-        db.share_project(room_id, ConnectionId(0), &[])
+        db.share_project(room_id, ConnectionId { epoch: 0, id: 0 }, &[])
             .await
             .unwrap();
         assert_eq!(db.project_count_excluding_admins().await.unwrap(), 2);
 
-        db.leave_room(ConnectionId(1)).await.unwrap();
+        db.leave_room(ConnectionId { epoch: 0, id: 1 })
+            .await
+            .unwrap();
         assert_eq!(db.project_count_excluding_admins().await.unwrap(), 0);
     }
 );
diff --git a/crates/collab/src/integration_tests.rs b/crates/collab/src/integration_tests.rs
index bee8f9a34f..2c2a301733 100644
--- a/crates/collab/src/integration_tests.rs
+++ b/crates/collab/src/integration_tests.rs
@@ -7,8 +7,8 @@ use crate::{
 use anyhow::anyhow;
 use call::{room, ActiveCall, ParticipantLocation, Room};
 use client::{
-    self, test::FakeHttpClient, Client, Connection, Credentials, EstablishConnectionError, PeerId,
-    User, UserStore, RECEIVE_TIMEOUT,
+    self, proto::PeerId, test::FakeHttpClient, Client, Connection, Credentials,
+    EstablishConnectionError, User, UserStore, RECEIVE_TIMEOUT,
 };
 use collections::{BTreeMap, HashMap, HashSet};
 use editor::{
@@ -6066,7 +6066,7 @@ async fn test_random_collaboration(
                     .user_connection_ids(removed_guest_id)
                     .collect::<Vec<_>>();
                 assert_eq!(user_connection_ids.len(), 1);
-                let removed_peer_id = PeerId(user_connection_ids[0].0);
+                let removed_peer_id = user_connection_ids[0].into();
                 let guest = clients.remove(guest_ix);
                 op_start_signals.remove(guest_ix);
                 server.forbid_connections();
@@ -6115,7 +6115,7 @@ async fn test_random_collaboration(
                     .user_connection_ids(user_id)
                     .collect::<Vec<_>>();
                 assert_eq!(user_connection_ids.len(), 1);
-                let peer_id = PeerId(user_connection_ids[0].0);
+                let peer_id = user_connection_ids[0].into();
                 server.disconnect_client(peer_id);
                 deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
                 operations += 1;
@@ -6429,7 +6429,7 @@ impl TestServer {
                         let connection_id = connection_id_rx.await.unwrap();
                         connection_killers
                             .lock()
-                            .insert(PeerId(connection_id.0), killed);
+                            .insert(connection_id.into(), killed);
                         Ok(client_conn)
                     }
                 })
diff --git a/crates/collab/src/rpc.rs b/crates/collab/src/rpc.rs
index 70802fa431..856eb36fb1 100644
--- a/crates/collab/src/rpc.rs
+++ b/crates/collab/src/rpc.rs
@@ -170,7 +170,7 @@ where
 impl Server {
     pub fn new(app_state: Arc<AppState>, executor: Executor) -> Arc<Self> {
         let mut server = Self {
-            peer: Peer::new(),
+            peer: Peer::new(0),
             app_state,
             executor,
             connection_pool: Default::default(),
@@ -457,9 +457,9 @@ impl Server {
                     move |duration| executor.sleep(duration)
                 });
 
-            tracing::info!(%user_id, %login, %connection_id, %address, "connection opened");
-            this.peer.send(connection_id, proto::Hello { peer_id: connection_id.0 })?;
-            tracing::info!(%user_id, %login, %connection_id, %address, "sent hello message");
+            tracing::info!(%user_id, %login, ?connection_id, %address, "connection opened");
+            this.peer.send(connection_id, proto::Hello { peer_id: Some(connection_id.into()) })?;
+            tracing::info!(%user_id, %login, ?connection_id, %address, "sent hello message");
 
             if let Some(send_connection_id) = send_connection_id.take() {
                 let _ = send_connection_id.send(connection_id);
@@ -521,7 +521,7 @@ impl Server {
                     _ = teardown.changed().fuse() => return Ok(()),
                     result = handle_io => {
                         if let Err(error) = result {
-                            tracing::error!(?error, %user_id, %login, %connection_id, %address, "error handling I/O");
+                            tracing::error!(?error, %user_id, %login, ?connection_id, %address, "error handling I/O");
                         }
                         break;
                     }
@@ -529,7 +529,7 @@ impl Server {
                     message = next_message => {
                         if let Some(message) = message {
                             let type_name = message.payload_type_name();
-                            let span = tracing::info_span!("receive message", %user_id, %login, %connection_id, %address, type_name);
+                            let span = tracing::info_span!("receive message", %user_id, %login, ?connection_id, %address, type_name);
                             let span_enter = span.enter();
                             if let Some(handler) = this.handlers.get(&message.payload_type_id()) {
                                 let is_background = message.is_background();
@@ -543,10 +543,10 @@ impl Server {
                                     foreground_message_handlers.push(handle_message);
                                 }
                             } else {
-                                tracing::error!(%user_id, %login, %connection_id, %address, "no message handler");
+                                tracing::error!(%user_id, %login, ?connection_id, %address, "no message handler");
                             }
                         } else {
-                            tracing::info!(%user_id, %login, %connection_id, %address, "connection closed");
+                            tracing::info!(%user_id, %login, ?connection_id, %address, "connection closed");
                             break;
                         }
                     }
@@ -554,9 +554,9 @@ impl Server {
             }
 
             drop(foreground_message_handlers);
-            tracing::info!(%user_id, %login, %connection_id, %address, "signing out");
+            tracing::info!(%user_id, %login, ?connection_id, %address, "signing out");
             if let Err(error) = sign_out(session, teardown, executor).await {
-                tracing::error!(%user_id, %login, %connection_id, %address, ?error, "error signing out");
+                tracing::error!(%user_id, %login, ?connection_id, %address, ?error, "error signing out");
             }
 
             Ok(())
@@ -1128,12 +1128,18 @@ async fn join_project(
     let collaborators = project
         .collaborators
         .iter()
-        .filter(|collaborator| collaborator.connection_id != session.connection_id.0 as i32)
-        .map(|collaborator| proto::Collaborator {
-            peer_id: collaborator.connection_id as u32,
-            replica_id: collaborator.replica_id.0 as u32,
-            user_id: collaborator.user_id.to_proto(),
+        .map(|collaborator| {
+            let peer_id = proto::PeerId {
+                epoch: collaborator.connection_epoch as u32,
+                id: collaborator.connection_id as u32,
+            };
+            proto::Collaborator {
+                peer_id: Some(peer_id),
+                replica_id: collaborator.replica_id.0 as u32,
+                user_id: collaborator.user_id.to_proto(),
+            }
         })
+        .filter(|collaborator| collaborator.peer_id != Some(session.connection_id.into()))
         .collect::<Vec<_>>();
     let worktrees = project
         .worktrees
@@ -1150,11 +1156,11 @@ async fn join_project(
         session
             .peer
             .send(
-                ConnectionId(collaborator.peer_id),
+                collaborator.peer_id.unwrap().into(),
                 proto::AddProjectCollaborator {
                     project_id: project_id.to_proto(),
                     collaborator: Some(proto::Collaborator {
-                        peer_id: session.connection_id.0,
+                        peer_id: Some(session.connection_id.into()),
                         replica_id: replica_id.0 as u32,
                         user_id: guest_user_id.to_proto(),
                     }),
@@ -1375,13 +1381,14 @@ where
             .await
             .project_collaborators(project_id, session.connection_id)
             .await?;
-        ConnectionId(
-            collaborators
-                .iter()
-                .find(|collaborator| collaborator.is_host)
-                .ok_or_else(|| anyhow!("host not found"))?
-                .connection_id as u32,
-        )
+        let host = collaborators
+            .iter()
+            .find(|collaborator| collaborator.is_host)
+            .ok_or_else(|| anyhow!("host not found"))?;
+        ConnectionId {
+            epoch: host.connection_epoch as u32,
+            id: host.connection_id as u32,
+        }
     };
 
     let payload = session
@@ -1409,7 +1416,10 @@ async fn save_buffer(
             .iter()
             .find(|collaborator| collaborator.is_host)
             .ok_or_else(|| anyhow!("host not found"))?;
-        ConnectionId(host.connection_id as u32)
+        ConnectionId {
+            epoch: host.connection_epoch as u32,
+            id: host.connection_id as u32,
+        }
     };
     let response_payload = session
         .peer
@@ -1421,11 +1431,17 @@ async fn save_buffer(
         .await
         .project_collaborators(project_id, session.connection_id)
         .await?;
-    collaborators
-        .retain(|collaborator| collaborator.connection_id != session.connection_id.0 as i32);
-    let project_connection_ids = collaborators
-        .iter()
-        .map(|collaborator| ConnectionId(collaborator.connection_id as u32));
+    collaborators.retain(|collaborator| {
+        let collaborator_connection = ConnectionId {
+            epoch: collaborator.connection_epoch as u32,
+            id: collaborator.connection_id as u32,
+        };
+        collaborator_connection != session.connection_id
+    });
+    let project_connection_ids = collaborators.iter().map(|collaborator| ConnectionId {
+        epoch: collaborator.connection_epoch as u32,
+        id: collaborator.connection_id as u32,
+    });
     broadcast(host_connection_id, project_connection_ids, |conn_id| {
         session
             .peer
@@ -1439,11 +1455,10 @@ async fn create_buffer_for_peer(
     request: proto::CreateBufferForPeer,
     session: Session,
 ) -> Result<()> {
-    session.peer.forward_send(
-        session.connection_id,
-        ConnectionId(request.peer_id),
-        request,
-    )?;
+    let peer_id = request.peer_id.ok_or_else(|| anyhow!("invalid peer id"))?;
+    session
+        .peer
+        .forward_send(session.connection_id, peer_id.into(), request)?;
     Ok(())
 }
 
@@ -1536,7 +1551,10 @@ async fn follow(
     session: Session,
 ) -> Result<()> {
     let project_id = ProjectId::from_proto(request.project_id);
-    let leader_id = ConnectionId(request.leader_id);
+    let leader_id = request
+        .leader_id
+        .ok_or_else(|| anyhow!("invalid leader id"))?
+        .into();
     let follower_id = session.connection_id;
     {
         let project_connection_ids = session
@@ -1556,14 +1574,17 @@ async fn follow(
         .await?;
     response_payload
         .views
-        .retain(|view| view.leader_id != Some(follower_id.0));
+        .retain(|view| view.leader_id != Some(follower_id.into()));
     response.send(response_payload)?;
     Ok(())
 }
 
 async fn unfollow(request: proto::Unfollow, session: Session) -> Result<()> {
     let project_id = ProjectId::from_proto(request.project_id);
-    let leader_id = ConnectionId(request.leader_id);
+    let leader_id = request
+        .leader_id
+        .ok_or_else(|| anyhow!("invalid leader id"))?
+        .into();
     let project_connection_ids = session
         .db()
         .await
@@ -1592,12 +1613,16 @@ async fn update_followers(request: proto::UpdateFollowers, session: Session) ->
         proto::update_followers::Variant::UpdateView(payload) => payload.leader_id,
         proto::update_followers::Variant::UpdateActiveView(payload) => payload.leader_id,
     });
-    for follower_id in &request.follower_ids {
-        let follower_id = ConnectionId(*follower_id);
-        if project_connection_ids.contains(&follower_id) && Some(follower_id.0) != leader_id {
-            session
-                .peer
-                .forward_send(session.connection_id, follower_id, request.clone())?;
+    for follower_peer_id in request.follower_ids.iter().copied() {
+        let follower_connection_id = follower_peer_id.into();
+        if project_connection_ids.contains(&follower_connection_id)
+            && Some(follower_peer_id) != leader_id
+        {
+            session.peer.forward_send(
+                session.connection_id,
+                follower_connection_id,
+                request.clone(),
+            )?;
         }
     }
     Ok(())
@@ -1912,13 +1937,19 @@ fn contact_for_user(
 
 fn room_updated(room: &proto::Room, peer: &Peer) {
     for participant in &room.participants {
-        peer.send(
-            ConnectionId(participant.peer_id),
-            proto::RoomUpdated {
-                room: Some(room.clone()),
-            },
-        )
-        .trace_err();
+        if let Some(peer_id) = participant
+            .peer_id
+            .ok_or_else(|| anyhow!("invalid participant peer id"))
+            .trace_err()
+        {
+            peer.send(
+                peer_id.into(),
+                proto::RoomUpdated {
+                    room: Some(room.clone()),
+                },
+            )
+            .trace_err();
+        }
     }
 }
 
@@ -2033,7 +2064,7 @@ fn project_left(project: &db::LeftProject, session: &Session) {
                     *connection_id,
                     proto::RemoveProjectCollaborator {
                         project_id: project.id.to_proto(),
-                        peer_id: session.connection_id.0,
+                        peer_id: Some(session.connection_id.into()),
                     },
                 )
                 .trace_err();
diff --git a/crates/collab_ui/src/collab_titlebar_item.rs b/crates/collab_ui/src/collab_titlebar_item.rs
index ab414e051b..2288f77cd3 100644
--- a/crates/collab_ui/src/collab_titlebar_item.rs
+++ b/crates/collab_ui/src/collab_titlebar_item.rs
@@ -1,6 +1,6 @@
 use crate::{contact_notification::ContactNotification, contacts_popover};
 use call::{ActiveCall, ParticipantLocation};
-use client::{Authenticate, ContactEventKind, PeerId, User, UserStore};
+use client::{proto::PeerId, Authenticate, ContactEventKind, User, UserStore};
 use clock::ReplicaId;
 use contacts_popover::ContactsPopover;
 use gpui::{
@@ -474,7 +474,7 @@ impl CollabTitlebarItem {
                         cx.dispatch_action(ToggleFollow(peer_id))
                     })
                     .with_tooltip::<ToggleFollow, _>(
-                        peer_id.0 as usize,
+                        peer_id.as_u64() as usize,
                         if is_followed {
                             format!("Unfollow {}", peer_github_login)
                         } else {
@@ -487,22 +487,24 @@ impl CollabTitlebarItem {
                     .boxed()
             } else if let ParticipantLocation::SharedProject { project_id } = location {
                 let user_id = user.id;
-                MouseEventHandler::<JoinProject>::new(peer_id.0 as usize, cx, move |_, _| content)
-                    .with_cursor_style(CursorStyle::PointingHand)
-                    .on_click(MouseButton::Left, move |_, cx| {
-                        cx.dispatch_action(JoinProject {
-                            project_id,
-                            follow_user_id: user_id,
-                        })
+                MouseEventHandler::<JoinProject>::new(peer_id.as_u64() as usize, cx, move |_, _| {
+                    content
+                })
+                .with_cursor_style(CursorStyle::PointingHand)
+                .on_click(MouseButton::Left, move |_, cx| {
+                    cx.dispatch_action(JoinProject {
+                        project_id,
+                        follow_user_id: user_id,
                     })
-                    .with_tooltip::<JoinProject, _>(
-                        peer_id.0 as usize,
-                        format!("Follow {} into external project", peer_github_login),
-                        Some(Box::new(FollowNextCollaborator)),
-                        theme.tooltip.clone(),
-                        cx,
-                    )
-                    .boxed()
+                })
+                .with_tooltip::<JoinProject, _>(
+                    peer_id.as_u64() as usize,
+                    format!("Follow {} into external project", peer_github_login),
+                    Some(Box::new(FollowNextCollaborator)),
+                    theme.tooltip.clone(),
+                    cx,
+                )
+                .boxed()
             } else {
                 content
             }
diff --git a/crates/collab_ui/src/contact_list.rs b/crates/collab_ui/src/contact_list.rs
index bc8b2947c4..48a4d1a2b5 100644
--- a/crates/collab_ui/src/contact_list.rs
+++ b/crates/collab_ui/src/contact_list.rs
@@ -2,7 +2,7 @@ use std::{mem, sync::Arc};
 
 use crate::contacts_popover;
 use call::ActiveCall;
-use client::{Contact, PeerId, User, UserStore};
+use client::{proto::PeerId, Contact, User, UserStore};
 use editor::{Cancel, Editor};
 use fuzzy::{match_strings, StringMatchCandidate};
 use gpui::{
@@ -465,7 +465,7 @@ impl ContactList {
                     room.remote_participants()
                         .iter()
                         .map(|(peer_id, participant)| StringMatchCandidate {
-                            id: peer_id.0 as usize,
+                            id: peer_id.as_u64() as usize,
                             string: participant.user.github_login.clone(),
                             char_bag: participant.user.github_login.chars().collect(),
                         }),
@@ -479,7 +479,7 @@ impl ContactList {
                 executor.clone(),
             ));
             for mat in matches {
-                let peer_id = PeerId(mat.candidate_id as u32);
+                let peer_id = PeerId::from_u64(mat.candidate_id as u64);
                 let participant = &room.remote_participants()[&peer_id];
                 participant_entries.push(ContactEntry::CallParticipant {
                     user: participant.user.clone(),
@@ -881,75 +881,80 @@ impl ContactList {
         let baseline_offset =
             row.name.text.baseline_offset(font_cache) + (theme.row_height - line_height) / 2.;
 
-        MouseEventHandler::<OpenSharedScreen>::new(peer_id.0 as usize, cx, |mouse_state, _| {
-            let tree_branch = *tree_branch.style_for(mouse_state, is_selected);
-            let row = theme.project_row.style_for(mouse_state, is_selected);
+        MouseEventHandler::<OpenSharedScreen>::new(
+            peer_id.as_u64() as usize,
+            cx,
+            |mouse_state, _| {
+                let tree_branch = *tree_branch.style_for(mouse_state, is_selected);
+                let row = theme.project_row.style_for(mouse_state, is_selected);
 
-            Flex::row()
-                .with_child(
-                    Stack::new()
-                        .with_child(
-                            Canvas::new(move |bounds, _, cx| {
-                                let start_x = bounds.min_x() + (bounds.width() / 2.)
-                                    - (tree_branch.width / 2.);
-                                let end_x = bounds.max_x();
-                                let start_y = bounds.min_y();
-                                let end_y = bounds.min_y() + baseline_offset - (cap_height / 2.);
+                Flex::row()
+                    .with_child(
+                        Stack::new()
+                            .with_child(
+                                Canvas::new(move |bounds, _, cx| {
+                                    let start_x = bounds.min_x() + (bounds.width() / 2.)
+                                        - (tree_branch.width / 2.);
+                                    let end_x = bounds.max_x();
+                                    let start_y = bounds.min_y();
+                                    let end_y =
+                                        bounds.min_y() + baseline_offset - (cap_height / 2.);
 
-                                cx.scene.push_quad(gpui::Quad {
-                                    bounds: RectF::from_points(
-                                        vec2f(start_x, start_y),
-                                        vec2f(
-                                            start_x + tree_branch.width,
-                                            if is_last { end_y } else { bounds.max_y() },
+                                    cx.scene.push_quad(gpui::Quad {
+                                        bounds: RectF::from_points(
+                                            vec2f(start_x, start_y),
+                                            vec2f(
+                                                start_x + tree_branch.width,
+                                                if is_last { end_y } else { bounds.max_y() },
+                                            ),
                                         ),
-                                    ),
-                                    background: Some(tree_branch.color),
-                                    border: gpui::Border::default(),
-                                    corner_radius: 0.,
-                                });
-                                cx.scene.push_quad(gpui::Quad {
-                                    bounds: RectF::from_points(
-                                        vec2f(start_x, end_y),
-                                        vec2f(end_x, end_y + tree_branch.width),
-                                    ),
-                                    background: Some(tree_branch.color),
-                                    border: gpui::Border::default(),
-                                    corner_radius: 0.,
-                                });
-                            })
+                                        background: Some(tree_branch.color),
+                                        border: gpui::Border::default(),
+                                        corner_radius: 0.,
+                                    });
+                                    cx.scene.push_quad(gpui::Quad {
+                                        bounds: RectF::from_points(
+                                            vec2f(start_x, end_y),
+                                            vec2f(end_x, end_y + tree_branch.width),
+                                        ),
+                                        background: Some(tree_branch.color),
+                                        border: gpui::Border::default(),
+                                        corner_radius: 0.,
+                                    });
+                                })
+                                .boxed(),
+                            )
+                            .constrained()
+                            .with_width(host_avatar_height)
                             .boxed(),
-                        )
-                        .constrained()
-                        .with_width(host_avatar_height)
-                        .boxed(),
-                )
-                .with_child(
-                    Svg::new("icons/disable_screen_sharing_12.svg")
-                        .with_color(row.icon.color)
-                        .constrained()
-                        .with_width(row.icon.width)
-                        .aligned()
-                        .left()
-                        .contained()
-                        .with_style(row.icon.container)
-                        .boxed(),
-                )
-                .with_child(
-                    Label::new("Screen".into(), row.name.text.clone())
-                        .aligned()
-                        .left()
-                        .contained()
-                        .with_style(row.name.container)
-                        .flex(1., false)
-                        .boxed(),
-                )
-                .constrained()
-                .with_height(theme.row_height)
-                .contained()
-                .with_style(row.container)
-                .boxed()
-        })
+                    )
+                    .with_child(
+                        Svg::new("icons/disable_screen_sharing_12.svg")
+                            .with_color(row.icon.color)
+                            .constrained()
+                            .with_width(row.icon.width)
+                            .aligned()
+                            .left()
+                            .contained()
+                            .with_style(row.icon.container)
+                            .boxed(),
+                    )
+                    .with_child(
+                        Label::new("Screen".into(), row.name.text.clone())
+                            .aligned()
+                            .left()
+                            .contained()
+                            .with_style(row.name.container)
+                            .flex(1., false)
+                            .boxed(),
+                    )
+                    .constrained()
+                    .with_height(theme.row_height)
+                    .contained()
+                    .with_style(row.container)
+                    .boxed()
+            },
+        )
         .with_cursor_style(CursorStyle::PointingHand)
         .on_click(MouseButton::Left, move |_, cx| {
             cx.dispatch_action(OpenSharedScreen { peer_id });
diff --git a/crates/project/src/lsp_command.rs b/crates/project/src/lsp_command.rs
index 3ea1261735..a0eb845581 100644
--- a/crates/project/src/lsp_command.rs
+++ b/crates/project/src/lsp_command.rs
@@ -3,7 +3,7 @@ use crate::{
 };
 use anyhow::{anyhow, Result};
 use async_trait::async_trait;
-use client::{proto, PeerId};
+use client::proto::{self, PeerId};
 use gpui::{AppContext, AsyncAppContext, ModelHandle};
 use language::{
     point_from_lsp, point_to_lsp,
diff --git a/crates/project/src/project.rs b/crates/project/src/project.rs
index 9b4a163af4..7f2fcb516f 100644
--- a/crates/project/src/project.rs
+++ b/crates/project/src/project.rs
@@ -7,7 +7,7 @@ pub mod worktree;
 mod project_tests;
 
 use anyhow::{anyhow, Context, Result};
-use client::{proto, Client, PeerId, TypedEnvelope, UserStore};
+use client::{proto, Client, TypedEnvelope, UserStore};
 use clock::ReplicaId;
 use collections::{hash_map, BTreeMap, HashMap, HashSet};
 use futures::{
@@ -15,7 +15,6 @@ use futures::{
     future::Shared,
     AsyncWriteExt, Future, FutureExt, StreamExt, TryFutureExt,
 };
-
 use gpui::{
     AnyModelHandle, AppContext, AsyncAppContext, Entity, ModelContext, ModelHandle,
     MutableAppContext, Task, UpgradeModelHandle, WeakModelHandle,
@@ -103,11 +102,11 @@ pub struct Project {
     user_store: ModelHandle<UserStore>,
     fs: Arc<dyn Fs>,
     client_state: Option<ProjectClientState>,
-    collaborators: HashMap<PeerId, Collaborator>,
+    collaborators: HashMap<proto::PeerId, Collaborator>,
     client_subscriptions: Vec<client::Subscription>,
     _subscriptions: Vec<gpui::Subscription>,
     opened_buffer: (watch::Sender<()>, watch::Receiver<()>),
-    shared_buffers: HashMap<PeerId, HashSet<u64>>,
+    shared_buffers: HashMap<proto::PeerId, HashSet<u64>>,
     #[allow(clippy::type_complexity)]
     loading_buffers: HashMap<
         ProjectPath,
@@ -164,7 +163,7 @@ enum ProjectClientState {
 
 #[derive(Clone, Debug)]
 pub struct Collaborator {
-    pub peer_id: PeerId,
+    pub peer_id: proto::PeerId,
     pub replica_id: ReplicaId,
 }
 
@@ -185,7 +184,7 @@ pub enum Event {
     },
     RemoteIdChanged(Option<u64>),
     DisconnectedFromHost,
-    CollaboratorLeft(PeerId),
+    CollaboratorLeft(proto::PeerId),
 }
 
 pub enum LanguageServerState {
@@ -555,7 +554,7 @@ impl Project {
             .await?;
         let mut collaborators = HashMap::default();
         for message in response.collaborators {
-            let collaborator = Collaborator::from_proto(message);
+            let collaborator = Collaborator::from_proto(message)?;
             collaborators.insert(collaborator.peer_id, collaborator);
         }
 
@@ -754,7 +753,7 @@ impl Project {
         }
     }
 
-    pub fn collaborators(&self) -> &HashMap<PeerId, Collaborator> {
+    pub fn collaborators(&self) -> &HashMap<proto::PeerId, Collaborator> {
         &self.collaborators
     }
 
@@ -4605,7 +4604,7 @@ impl Project {
             .take()
             .ok_or_else(|| anyhow!("empty collaborator"))?;
 
-        let collaborator = Collaborator::from_proto(collaborator);
+        let collaborator = Collaborator::from_proto(collaborator)?;
         this.update(&mut cx, |this, cx| {
             this.collaborators
                 .insert(collaborator.peer_id, collaborator);
@@ -4622,7 +4621,10 @@ impl Project {
         mut cx: AsyncAppContext,
     ) -> Result<()> {
         this.update(&mut cx, |this, cx| {
-            let peer_id = PeerId(envelope.payload.peer_id);
+            let peer_id = envelope
+                .payload
+                .peer_id
+                .ok_or_else(|| anyhow!("invalid peer id"))?;
             let replica_id = this
                 .collaborators
                 .remove(&peer_id)
@@ -5489,7 +5491,7 @@ impl Project {
     fn serialize_project_transaction_for_peer(
         &mut self,
         project_transaction: ProjectTransaction,
-        peer_id: PeerId,
+        peer_id: proto::PeerId,
         cx: &AppContext,
     ) -> proto::ProjectTransaction {
         let mut serialized_transaction = proto::ProjectTransaction {
@@ -5545,7 +5547,7 @@ impl Project {
     fn create_buffer_for_peer(
         &mut self,
         buffer: &ModelHandle<Buffer>,
-        peer_id: PeerId,
+        peer_id: proto::PeerId,
         cx: &AppContext,
     ) -> u64 {
         let buffer_id = buffer.read(cx).remote_id();
@@ -5563,7 +5565,7 @@ impl Project {
 
                             client.send(proto::CreateBufferForPeer {
                                 project_id,
-                                peer_id: peer_id.0,
+                                peer_id: Some(peer_id),
                                 variant: Some(proto::create_buffer_for_peer::Variant::State(state)),
                             })?;
 
@@ -5580,7 +5582,7 @@ impl Project {
                                 let is_last = operations.is_empty();
                                 client.send(proto::CreateBufferForPeer {
                                     project_id,
-                                    peer_id: peer_id.0,
+                                    peer_id: Some(peer_id),
                                     variant: Some(proto::create_buffer_for_peer::Variant::Chunk(
                                         proto::BufferChunk {
                                             buffer_id,
@@ -6036,11 +6038,11 @@ impl Entity for Project {
 }
 
 impl Collaborator {
-    fn from_proto(message: proto::Collaborator) -> Self {
-        Self {
-            peer_id: PeerId(message.peer_id),
+    fn from_proto(message: proto::Collaborator) -> Result<Self> {
+        Ok(Self {
+            peer_id: message.peer_id.ok_or_else(|| anyhow!("invalid peer id"))?,
             replica_id: message.replica_id as ReplicaId,
-        }
+        })
     }
 }
 
diff --git a/crates/rpc/proto/zed.proto b/crates/rpc/proto/zed.proto
index cf58adfe0b..064bf6f50a 100644
--- a/crates/rpc/proto/zed.proto
+++ b/crates/rpc/proto/zed.proto
@@ -1,10 +1,15 @@
 syntax = "proto3";
 package zed.messages;
 
+message PeerId {
+    uint32 epoch = 1;
+    uint32 id = 2;
+}
+
 message Envelope {
     uint32 id = 1;
     optional uint32 responding_to = 2;
-    optional uint32 original_sender_id = 3;
+    PeerId original_sender_id = 3;
     oneof payload {
         Hello hello = 4;
         Ack ack = 5;
@@ -125,7 +130,7 @@ message Envelope {
 // Messages
 
 message Hello {
-    uint32 peer_id = 1;
+    PeerId peer_id = 1;
 }
 
 message Ping {}
@@ -167,7 +172,7 @@ message Room {
 
 message Participant {
     uint64 user_id = 1;
-    uint32 peer_id = 2;
+    PeerId peer_id = 2;
     repeated ParticipantProject projects = 3;
     ParticipantLocation location = 4;
 }
@@ -319,7 +324,7 @@ message AddProjectCollaborator {
 
 message RemoveProjectCollaborator {
     uint64 project_id = 1;
-    uint32 peer_id = 2;
+    PeerId peer_id = 2;
 }
 
 message GetDefinition {
@@ -438,7 +443,7 @@ message OpenBufferResponse {
 
 message CreateBufferForPeer {
     uint64 project_id = 1;
-    uint32 peer_id = 2;
+    PeerId peer_id = 2;
     oneof variant {
         BufferState state = 3;
         BufferChunk chunk = 4;
@@ -794,7 +799,7 @@ message UpdateDiagnostics {
 
 message Follow {
     uint64 project_id = 1;
-    uint32 leader_id = 2;
+    PeerId leader_id = 2;
 }
 
 message FollowResponse {
@@ -804,7 +809,7 @@ message FollowResponse {
 
 message UpdateFollowers {
     uint64 project_id = 1;
-    repeated uint32 follower_ids = 2;
+    repeated PeerId follower_ids = 2;
     oneof variant {
         UpdateActiveView update_active_view = 3;
         View create_view = 4;
@@ -814,7 +819,7 @@ message UpdateFollowers {
 
 message Unfollow {
     uint64 project_id = 1;
-    uint32 leader_id = 2;
+    PeerId leader_id = 2;
 }
 
 message GetPrivateUserInfo {}
@@ -828,12 +833,12 @@ message GetPrivateUserInfoResponse {
 
 message UpdateActiveView {
     optional uint64 id = 1;
-    optional uint32 leader_id = 2;
+    optional PeerId leader_id = 2;
 }
 
 message UpdateView {
     uint64 id = 1;
-    optional uint32 leader_id = 2;
+    optional PeerId leader_id = 2;
 
     oneof variant {
         Editor editor = 3;
@@ -849,7 +854,7 @@ message UpdateView {
 
 message View {
     uint64 id = 1;
-    optional uint32 leader_id = 2;
+    optional PeerId leader_id = 2;
 
     oneof variant {
         Editor editor = 3;
@@ -865,7 +870,7 @@ message View {
 }
 
 message Collaborator {
-    uint32 peer_id = 1;
+    PeerId peer_id = 1;
     uint32 replica_id = 2;
     uint64 user_id = 3;
 }
diff --git a/crates/rpc/src/macros.rs b/crates/rpc/src/macros.rs
index 38d35893ee..ebed976968 100644
--- a/crates/rpc/src/macros.rs
+++ b/crates/rpc/src/macros.rs
@@ -6,7 +6,10 @@ macro_rules! messages {
                 $(Some(envelope::Payload::$name(payload)) => {
                     Some(Box::new(TypedEnvelope {
                         sender_id,
-                        original_sender_id: envelope.original_sender_id.map(PeerId),
+                        original_sender_id: envelope.original_sender_id.map(|original_sender| PeerId {
+                            epoch: original_sender.epoch,
+                            id: original_sender.id
+                        }),
                         message_id: envelope.id,
                         payload,
                     }))
@@ -24,7 +27,7 @@ macro_rules! messages {
                     self,
                     id: u32,
                     responding_to: Option<u32>,
-                    original_sender_id: Option<u32>,
+                    original_sender_id: Option<PeerId>,
                 ) -> Envelope {
                     Envelope {
                         id,
diff --git a/crates/rpc/src/peer.rs b/crates/rpc/src/peer.rs
index 66ba6a4029..43e4dfbde8 100644
--- a/crates/rpc/src/peer.rs
+++ b/crates/rpc/src/peer.rs
@@ -1,5 +1,5 @@
 use super::{
-    proto::{self, AnyTypedEnvelope, EnvelopedMessage, MessageStream, RequestMessage},
+    proto::{self, AnyTypedEnvelope, EnvelopedMessage, MessageStream, PeerId, RequestMessage},
     Connection,
 };
 use anyhow::{anyhow, Context, Result};
@@ -11,9 +11,8 @@ use futures::{
 };
 use parking_lot::{Mutex, RwLock};
 use serde::{ser::SerializeStruct, Serialize};
-use std::sync::atomic::Ordering::SeqCst;
+use std::{fmt, sync::atomic::Ordering::SeqCst};
 use std::{
-    fmt,
     future::Future,
     marker::PhantomData,
     sync::{
@@ -25,20 +24,32 @@ use std::{
 use tracing::instrument;
 
 #[derive(Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Serialize)]
-pub struct ConnectionId(pub u32);
+pub struct ConnectionId {
+    pub epoch: u32,
+    pub id: u32,
+}
 
-impl fmt::Display for ConnectionId {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0.fmt(f)
+impl Into<PeerId> for ConnectionId {
+    fn into(self) -> PeerId {
+        PeerId {
+            epoch: self.epoch,
+            id: self.id,
+        }
     }
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
-pub struct PeerId(pub u32);
+impl From<PeerId> for ConnectionId {
+    fn from(peer_id: PeerId) -> Self {
+        Self {
+            epoch: peer_id.epoch,
+            id: peer_id.id,
+        }
+    }
+}
 
-impl fmt::Display for PeerId {
+impl fmt::Display for ConnectionId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0.fmt(f)
+        write!(f, "{}/{}", self.epoch, self.id)
     }
 }
 
@@ -70,6 +81,7 @@ pub struct TypedEnvelope<T> {
 impl<T> TypedEnvelope<T> {
     pub fn original_sender_id(&self) -> Result<PeerId> {
         self.original_sender_id
+            .clone()
             .ok_or_else(|| anyhow!("missing original_sender_id"))
     }
 }
@@ -85,6 +97,7 @@ impl<T: RequestMessage> TypedEnvelope<T> {
 }
 
 pub struct Peer {
+    epoch: u32,
     pub connections: RwLock<HashMap<ConnectionId, ConnectionState>>,
     next_connection_id: AtomicU32,
 }
@@ -105,8 +118,9 @@ const WRITE_TIMEOUT: Duration = Duration::from_secs(2);
 pub const RECEIVE_TIMEOUT: Duration = Duration::from_secs(5);
 
 impl Peer {
-    pub fn new() -> Arc<Self> {
+    pub fn new(epoch: u32) -> Arc<Self> {
         Arc::new(Self {
+            epoch,
             connections: Default::default(),
             next_connection_id: Default::default(),
         })
@@ -138,7 +152,10 @@ impl Peer {
         let (mut incoming_tx, incoming_rx) = mpsc::channel(INCOMING_BUFFER_SIZE);
         let (outgoing_tx, mut outgoing_rx) = mpsc::unbounded();
 
-        let connection_id = ConnectionId(self.next_connection_id.fetch_add(1, SeqCst));
+        let connection_id = ConnectionId {
+            epoch: self.epoch,
+            id: self.next_connection_id.fetch_add(1, SeqCst),
+        };
         let connection_state = ConnectionState {
             outgoing_tx,
             next_message_id: Default::default(),
@@ -150,12 +167,12 @@ impl Peer {
         let this = self.clone();
         let response_channels = connection_state.response_channels.clone();
         let handle_io = async move {
-            tracing::debug!(%connection_id, "handle io future: start");
+            tracing::debug!(?connection_id, "handle io future: start");
 
             let _end_connection = util::defer(|| {
                 response_channels.lock().take();
                 this.connections.write().remove(&connection_id);
-                tracing::debug!(%connection_id, "handle io future: end");
+                tracing::debug!(?connection_id, "handle io future: end");
             });
 
             // Send messages on this frequency so the connection isn't closed.
@@ -167,68 +184,68 @@ impl Peer {
             futures::pin_mut!(receive_timeout);
 
             loop {
-                tracing::debug!(%connection_id, "outer loop iteration start");
+                tracing::debug!(?connection_id, "outer loop iteration start");
                 let read_message = reader.read().fuse();
                 futures::pin_mut!(read_message);
 
                 loop {
-                    tracing::debug!(%connection_id, "inner loop iteration start");
+                    tracing::debug!(?connection_id, "inner loop iteration start");
                     futures::select_biased! {
                         outgoing = outgoing_rx.next().fuse() => match outgoing {
                             Some(outgoing) => {
-                                tracing::debug!(%connection_id, "outgoing rpc message: writing");
+                                tracing::debug!(?connection_id, "outgoing rpc message: writing");
                                 futures::select_biased! {
                                     result = writer.write(outgoing).fuse() => {
-                                        tracing::debug!(%connection_id, "outgoing rpc message: done writing");
+                                        tracing::debug!(?connection_id, "outgoing rpc message: done writing");
                                         result.context("failed to write RPC message")?;
-                                        tracing::debug!(%connection_id, "keepalive interval: resetting after sending message");
+                                        tracing::debug!(?connection_id, "keepalive interval: resetting after sending message");
                                         keepalive_timer.set(create_timer(KEEPALIVE_INTERVAL).fuse());
                                     }
                                     _ = create_timer(WRITE_TIMEOUT).fuse() => {
-                                        tracing::debug!(%connection_id, "outgoing rpc message: writing timed out");
+                                        tracing::debug!(?connection_id, "outgoing rpc message: writing timed out");
                                         Err(anyhow!("timed out writing message"))?;
                                     }
                                 }
                             }
                             None => {
-                                tracing::debug!(%connection_id, "outgoing rpc message: channel closed");
+                                tracing::debug!(?connection_id, "outgoing rpc message: channel closed");
                                 return Ok(())
                             },
                         },
                         _ = keepalive_timer => {
-                            tracing::debug!(%connection_id, "keepalive interval: pinging");
+                            tracing::debug!(?connection_id, "keepalive interval: pinging");
                             futures::select_biased! {
                                 result = writer.write(proto::Message::Ping).fuse() => {
-                                    tracing::debug!(%connection_id, "keepalive interval: done pinging");
+                                    tracing::debug!(?connection_id, "keepalive interval: done pinging");
                                     result.context("failed to send keepalive")?;
-                                    tracing::debug!(%connection_id, "keepalive interval: resetting after pinging");
+                                    tracing::debug!(?connection_id, "keepalive interval: resetting after pinging");
                                     keepalive_timer.set(create_timer(KEEPALIVE_INTERVAL).fuse());
                                 }
                                 _ = create_timer(WRITE_TIMEOUT).fuse() => {
-                                    tracing::debug!(%connection_id, "keepalive interval: pinging timed out");
+                                    tracing::debug!(?connection_id, "keepalive interval: pinging timed out");
                                     Err(anyhow!("timed out sending keepalive"))?;
                                 }
                             }
                         }
                         incoming = read_message => {
                             let incoming = incoming.context("error reading rpc message from socket")?;
-                            tracing::debug!(%connection_id, "incoming rpc message: received");
-                            tracing::debug!(%connection_id, "receive timeout: resetting");
+                            tracing::debug!(?connection_id, "incoming rpc message: received");
+                            tracing::debug!(?connection_id, "receive timeout: resetting");
                             receive_timeout.set(create_timer(RECEIVE_TIMEOUT).fuse());
                             if let proto::Message::Envelope(incoming) = incoming {
-                                tracing::debug!(%connection_id, "incoming rpc message: processing");
+                                tracing::debug!(?connection_id, "incoming rpc message: processing");
                                 futures::select_biased! {
                                     result = incoming_tx.send(incoming).fuse() => match result {
                                         Ok(_) => {
-                                            tracing::debug!(%connection_id, "incoming rpc message: processed");
+                                            tracing::debug!(?connection_id, "incoming rpc message: processed");
                                         }
                                         Err(_) => {
-                                            tracing::debug!(%connection_id, "incoming rpc message: channel closed");
+                                            tracing::debug!(?connection_id, "incoming rpc message: channel closed");
                                             return Ok(())
                                         }
                                     },
                                     _ = create_timer(WRITE_TIMEOUT).fuse() => {
-                                        tracing::debug!(%connection_id, "incoming rpc message: processing timed out");
+                                        tracing::debug!(?connection_id, "incoming rpc message: processing timed out");
                                         Err(anyhow!("timed out processing incoming message"))?
                                     }
                                 }
@@ -236,7 +253,7 @@ impl Peer {
                             break;
                         },
                         _ = receive_timeout => {
-                            tracing::debug!(%connection_id, "receive timeout: delay between messages too long");
+                            tracing::debug!(?connection_id, "receive timeout: delay between messages too long");
                             Err(anyhow!("delay between messages too long"))?
                         }
                     }
@@ -255,16 +272,12 @@ impl Peer {
                 let message_id = incoming.id;
                 tracing::debug!(?incoming, "incoming message future: start");
                 let _end = util::defer(move || {
-                    tracing::debug!(
-                        %connection_id,
-                        message_id,
-                        "incoming message future: end"
-                    );
+                    tracing::debug!(?connection_id, message_id, "incoming message future: end");
                 });
 
                 if let Some(responding_to) = incoming.responding_to {
                     tracing::debug!(
-                        %connection_id,
+                        ?connection_id,
                         message_id,
                         responding_to,
                         "incoming response: received"
@@ -274,7 +287,7 @@ impl Peer {
                         let requester_resumed = oneshot::channel();
                         if let Err(error) = tx.send((incoming, requester_resumed.0)) {
                             tracing::debug!(
-                                %connection_id,
+                                ?connection_id,
                                 message_id,
                                 responding_to = responding_to,
                                 ?error,
@@ -283,21 +296,21 @@ impl Peer {
                         }
 
                         tracing::debug!(
-                            %connection_id,
+                            ?connection_id,
                             message_id,
                             responding_to,
                             "incoming response: waiting to resume requester"
                         );
                         let _ = requester_resumed.1.await;
                         tracing::debug!(
-                            %connection_id,
+                            ?connection_id,
                             message_id,
                             responding_to,
                             "incoming response: requester resumed"
                         );
                     } else {
                         tracing::warn!(
-                            %connection_id,
+                            ?connection_id,
                             message_id,
                             responding_to,
                             "incoming response: unknown request"
@@ -306,14 +319,10 @@ impl Peer {
 
                     None
                 } else {
-                    tracing::debug!(
-                        %connection_id,
-                        message_id,
-                        "incoming message: received"
-                    );
+                    tracing::debug!(?connection_id, message_id, "incoming message: received");
                     proto::build_typed_envelope(connection_id, incoming).or_else(|| {
                         tracing::error!(
-                            %connection_id,
+                            ?connection_id,
                             message_id,
                             "unable to construct a typed envelope"
                         );
@@ -345,6 +354,7 @@ impl Peer {
 
     pub fn reset(&self) {
         self.connections.write().clear();
+        self.next_connection_id.store(0, SeqCst);
     }
 
     pub fn request<T: RequestMessage>(
@@ -384,7 +394,7 @@ impl Peer {
                 .unbounded_send(proto::Message::Envelope(request.into_envelope(
                     message_id,
                     None,
-                    original_sender_id.map(|id| id.0),
+                    original_sender_id.map(Into::into),
                 )))
                 .map_err(|_| anyhow!("connection was closed"))?;
             Ok(())
@@ -433,7 +443,7 @@ impl Peer {
             .unbounded_send(proto::Message::Envelope(message.into_envelope(
                 message_id,
                 None,
-                Some(sender_id.0),
+                Some(sender_id.into()),
             )))?;
         Ok(())
     }
@@ -480,7 +490,7 @@ impl Peer {
         let connections = self.connections.read();
         let connection = connections
             .get(&connection_id)
-            .ok_or_else(|| anyhow!("no such connection: {}", connection_id))?;
+            .ok_or_else(|| anyhow!("no such connection: {:?}", connection_id))?;
         Ok(connection.clone())
     }
 }
@@ -515,9 +525,9 @@ mod tests {
         let executor = cx.foreground();
 
         // create 2 clients connected to 1 server
-        let server = Peer::new();
-        let client1 = Peer::new();
-        let client2 = Peer::new();
+        let server = Peer::new(0);
+        let client1 = Peer::new(0);
+        let client2 = Peer::new(0);
 
         let (client1_to_server_conn, server_to_client_1_conn, _kill) =
             Connection::in_memory(cx.background());
@@ -609,8 +619,8 @@ mod tests {
     #[gpui::test(iterations = 50)]
     async fn test_order_of_response_and_incoming(cx: &mut TestAppContext) {
         let executor = cx.foreground();
-        let server = Peer::new();
-        let client = Peer::new();
+        let server = Peer::new(0);
+        let client = Peer::new(0);
 
         let (client_to_server_conn, server_to_client_conn, _kill) =
             Connection::in_memory(cx.background());
@@ -707,8 +717,8 @@ mod tests {
     #[gpui::test(iterations = 50)]
     async fn test_dropping_request_before_completion(cx: &mut TestAppContext) {
         let executor = cx.foreground();
-        let server = Peer::new();
-        let client = Peer::new();
+        let server = Peer::new(0);
+        let client = Peer::new(0);
 
         let (client_to_server_conn, server_to_client_conn, _kill) =
             Connection::in_memory(cx.background());
@@ -822,7 +832,7 @@ mod tests {
 
         let (client_conn, mut server_conn, _kill) = Connection::in_memory(cx.background());
 
-        let client = Peer::new();
+        let client = Peer::new(0);
         let (connection_id, io_handler, mut incoming) =
             client.add_test_connection(client_conn, cx.background());
 
@@ -857,7 +867,7 @@ mod tests {
         let executor = cx.foreground();
         let (client_conn, mut server_conn, _kill) = Connection::in_memory(cx.background());
 
-        let client = Peer::new();
+        let client = Peer::new(0);
         let (connection_id, io_handler, mut incoming) =
             client.add_test_connection(client_conn, cx.background());
         executor.spawn(io_handler).detach();
diff --git a/crates/rpc/src/proto.rs b/crates/rpc/src/proto.rs
index 6d9bc9a0aa..77d82ec308 100644
--- a/crates/rpc/src/proto.rs
+++ b/crates/rpc/src/proto.rs
@@ -1,14 +1,16 @@
-use super::{entity_messages, messages, request_messages, ConnectionId, PeerId, TypedEnvelope};
+use super::{entity_messages, messages, request_messages, ConnectionId, TypedEnvelope};
 use anyhow::{anyhow, Result};
 use async_tungstenite::tungstenite::Message as WebSocketMessage;
 use futures::{SinkExt as _, StreamExt as _};
 use prost::Message as _;
 use serde::Serialize;
 use std::any::{Any, TypeId};
-use std::{cmp, iter, mem};
+use std::fmt;
+use std::str::FromStr;
 use std::{
+    cmp,
     fmt::Debug,
-    io,
+    io, iter, mem,
     time::{Duration, SystemTime, UNIX_EPOCH},
 };
 
@@ -21,7 +23,7 @@ pub trait EnvelopedMessage: Clone + Debug + Serialize + Sized + Send + Sync + 's
         self,
         id: u32,
         responding_to: Option<u32>,
-        original_sender_id: Option<u32>,
+        original_sender_id: Option<PeerId>,
     ) -> Envelope;
     fn from_envelope(envelope: Envelope) -> Option<Self>;
 }
@@ -70,7 +72,67 @@ impl<T: EnvelopedMessage> AnyTypedEnvelope for TypedEnvelope<T> {
     }
 
     fn original_sender_id(&self) -> Option<PeerId> {
-        self.original_sender_id
+        self.original_sender_id.clone()
+    }
+}
+
+impl PeerId {
+    pub fn from_u64(peer_id: u64) -> Self {
+        let epoch = (peer_id >> 32) as u32;
+        let id = peer_id as u32;
+        Self { epoch, id }
+    }
+
+    pub fn as_u64(self) -> u64 {
+        ((self.epoch as u64) << 32) | (self.id as u64)
+    }
+}
+
+impl Copy for PeerId {}
+
+impl Eq for PeerId {}
+
+impl Ord for PeerId {
+    fn cmp(&self, other: &Self) -> cmp::Ordering {
+        self.epoch
+            .cmp(&other.epoch)
+            .then_with(|| self.id.cmp(&other.id))
+    }
+}
+
+impl PartialOrd for PeerId {
+    fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl std::hash::Hash for PeerId {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.epoch.hash(state);
+        self.id.hash(state);
+    }
+}
+
+impl fmt::Display for PeerId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}/{}", self.epoch, self.id)
+    }
+}
+
+impl FromStr for PeerId {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut components = s.split('/');
+        let epoch = components
+            .next()
+            .ok_or_else(|| anyhow!("invalid peer id {:?}", s))?
+            .parse()?;
+        let id = components
+            .next()
+            .ok_or_else(|| anyhow!("invalid peer id {:?}", s))?
+            .parse()?;
+        Ok(PeerId { epoch, id })
     }
 }
 
@@ -477,4 +539,25 @@ mod tests {
         stream.read().await.unwrap();
         assert!(stream.encoding_buffer.capacity() <= MAX_BUFFER_LEN);
     }
+
+    #[gpui::test]
+    fn test_converting_peer_id_from_and_to_u64() {
+        let peer_id = PeerId { epoch: 10, id: 3 };
+        assert_eq!(PeerId::from_u64(peer_id.as_u64()), peer_id);
+        let peer_id = PeerId {
+            epoch: u32::MAX,
+            id: 3,
+        };
+        assert_eq!(PeerId::from_u64(peer_id.as_u64()), peer_id);
+        let peer_id = PeerId {
+            epoch: 10,
+            id: u32::MAX,
+        };
+        assert_eq!(PeerId::from_u64(peer_id.as_u64()), peer_id);
+        let peer_id = PeerId {
+            epoch: u32::MAX,
+            id: u32::MAX,
+        };
+        assert_eq!(PeerId::from_u64(peer_id.as_u64()), peer_id);
+    }
 }
diff --git a/crates/rpc/src/rpc.rs b/crates/rpc/src/rpc.rs
index 1d4a4496d0..d06f1c1c5c 100644
--- a/crates/rpc/src/rpc.rs
+++ b/crates/rpc/src/rpc.rs
@@ -6,4 +6,4 @@ pub use conn::Connection;
 pub use peer::*;
 mod macros;
 
-pub const PROTOCOL_VERSION: u32 = 41;
+pub const PROTOCOL_VERSION: u32 = 42;
diff --git a/crates/workspace/src/item.rs b/crates/workspace/src/item.rs
index 14f847fd54..bd00272c94 100644
--- a/crates/workspace/src/item.rs
+++ b/crates/workspace/src/item.rs
@@ -280,7 +280,7 @@ impl<T: Item> ItemHandle for ViewHandle<T> {
                     proto::update_followers::Variant::CreateView(proto::View {
                         id: followed_item.id() as u64,
                         variant: Some(message),
-                        leader_id: workspace.leader_for_pane(&pane).map(|id| id.0),
+                        leader_id: workspace.leader_for_pane(&pane),
                     }),
                     cx,
                 );
@@ -334,7 +334,7 @@ impl<T: Item> ItemHandle for ViewHandle<T> {
                                             proto::UpdateView {
                                                 id: item.id() as u64,
                                                 variant: pending_update.borrow_mut().take(),
-                                                leader_id: leader_id.map(|id| id.0),
+                                                leader_id,
                                             },
                                         ),
                                         cx,
diff --git a/crates/workspace/src/shared_screen.rs b/crates/workspace/src/shared_screen.rs
index 7dee642423..d292ece3d5 100644
--- a/crates/workspace/src/shared_screen.rs
+++ b/crates/workspace/src/shared_screen.rs
@@ -3,7 +3,7 @@ use crate::{
 };
 use anyhow::{anyhow, Result};
 use call::participant::{Frame, RemoteVideoTrack};
-use client::{PeerId, User};
+use client::{proto::PeerId, User};
 use futures::StreamExt;
 use gpui::{
     elements::*,
diff --git a/crates/workspace/src/workspace.rs b/crates/workspace/src/workspace.rs
index 387a18006a..46e790b892 100644
--- a/crates/workspace/src/workspace.rs
+++ b/crates/workspace/src/workspace.rs
@@ -25,7 +25,10 @@ use std::{
 
 use anyhow::{anyhow, Context, Result};
 use call::ActiveCall;
-use client::{proto, Client, PeerId, TypedEnvelope, UserStore};
+use client::{
+    proto::{self, PeerId},
+    Client, TypedEnvelope, UserStore,
+};
 use collections::{hash_map, HashMap, HashSet};
 use dock::{Dock, DockDefaultItemFactory, ToggleDockButton};
 use drag_and_drop::DragAndDrop;
@@ -1441,7 +1444,7 @@ impl Workspace {
         self.update_followers(
             proto::update_followers::Variant::UpdateActiveView(proto::UpdateActiveView {
                 id: self.active_item(cx).map(|item| item.id() as u64),
-                leader_id: self.leader_for_pane(&pane).map(|id| id.0),
+                leader_id: self.leader_for_pane(&pane),
             }),
             cx,
         );
@@ -1620,7 +1623,7 @@ impl Workspace {
         let project_id = self.project.read(cx).remote_id()?;
         let request = self.client.request(proto::Follow {
             project_id,
-            leader_id: leader_id.0,
+            leader_id: Some(leader_id),
         });
         Some(cx.spawn_weak(|this, mut cx| async move {
             let response = request.await?;
@@ -1692,7 +1695,7 @@ impl Workspace {
                         self.client
                             .send(proto::Unfollow {
                                 project_id,
-                                leader_id: leader_id.0,
+                                leader_id: Some(leader_id),
                             })
                             .log_err();
                     }
@@ -1888,7 +1891,7 @@ impl Workspace {
                     .panes()
                     .iter()
                     .flat_map(|pane| {
-                        let leader_id = this.leader_for_pane(pane).map(|id| id.0);
+                        let leader_id = this.leader_for_pane(pane);
                         pane.read(cx).items().filter_map({
                             let cx = &cx;
                             move |item| {
@@ -1997,7 +2000,7 @@ impl Workspace {
                     .get(&leader_id)
                     .map(|c| c.replica_id)
             })
-            .ok_or_else(|| anyhow!("no such collaborator {}", leader_id))?;
+            .ok_or_else(|| anyhow!("no such collaborator {:?}", leader_id))?;
 
         let item_builders = cx.update(|cx| {
             cx.default_global::<FollowableItemBuilders>()
@@ -2077,7 +2080,7 @@ impl Workspace {
             self.client
                 .send(proto::UpdateFollowers {
                     project_id,
-                    follower_ids: self.leader_state.followers.iter().map(|f| f.0).collect(),
+                    follower_ids: self.leader_state.followers.iter().copied().collect(),
                     variant: Some(update),
                 })
                 .log_err();