diff --git a/package.json b/package.json
index de210388f..0eeca5659 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,7 @@
     "types": "src/index.ts",
     "type": "module",
     "license": "MIT",
-    "version": "0.0.11",
+    "version": "0.0.12",
     "devDependencies": {
         "@types/jest": "^29.5.3",
         "@typescript-eslint/eslint-plugin": "^6.2.1",
diff --git a/src/coValue.ts b/src/coValue.ts
index afea7cbeb..408b0c632 100644
--- a/src/coValue.ts
+++ b/src/coValue.ts
@@ -148,7 +148,7 @@ export class CoValue {
     tryAddTransactions(
         sessionID: SessionID,
         newTransactions: Transaction[],
-        newHash: Hash,
+        givenExpectedNewHash: Hash | undefined,
         newSignature: Signature
     ): boolean {
         const signerID = getAgentSignerID(
@@ -171,16 +171,16 @@ export class CoValue {
             newTransactions
         );
 
-        if (newHash !== expectedNewHash) {
-            console.warn("Invalid hash", { newHash, expectedNewHash });
+        if (givenExpectedNewHash && givenExpectedNewHash !== expectedNewHash) {
+            console.warn("Invalid hash", { expectedNewHash, givenExpectedNewHash });
             return false;
         }
 
-        if (!verify(newSignature, newHash, signerID)) {
+        if (!verify(newSignature, expectedNewHash, signerID)) {
             console.warn(
                 "Invalid signature",
                 newSignature,
-                newHash,
+                expectedNewHash,
                 signerID
             );
             return false;
@@ -192,7 +192,7 @@ export class CoValue {
 
         this.sessions[sessionID] = {
             transactions,
-            lastHash: newHash,
+            lastHash: expectedNewHash,
             streamingHash: newStreamingHash,
             lastSignature: newSignature,
         };
@@ -517,7 +517,6 @@ export class CoValue {
                                         sessionID as SessionID
                                     ] || 0,
                                 newTransactions,
-                                lastHash: log.lastHash,
                                 lastSignature: log.lastSignature,
                             },
                         ];
diff --git a/src/sync.test.ts b/src/sync.test.ts
index 92edce4d1..880703cd2 100644
--- a/src/sync.test.ts
+++ b/src/sync.test.ts
@@ -9,7 +9,12 @@ import {
     WritableStream,
     TransformStream,
 } from "isomorphic-streams";
-import { connectedPeers, newStreamPair, randomAnonymousAccountAndSessionID, shouldNotResolve } from "./testUtils.js";
+import {
+    connectedPeers,
+    newStreamPair,
+    randomAnonymousAccountAndSessionID,
+    shouldNotResolve,
+} from "./testUtils.js";
 import { AccountID } from "./account.js";
 
 test("Node replies with initial tx and header to empty subscribe", async () => {
@@ -86,7 +91,6 @@ test("Node replies with initial tx and header to empty subscribe", async () => {
                         ],
                     },
                 ],
-                lastHash: map.coValue.sessions[node.ownSessionID]!.lastHash!,
                 lastSignature:
                     map.coValue.sessions[node.ownSessionID]!.lastSignature!,
             },
@@ -165,7 +169,6 @@ test("Node replies with only new tx to subscribe with some known state", async (
                         ],
                     },
                 ],
-                lastHash: map.coValue.sessions[node.ownSessionID]!.lastHash!,
                 lastSignature:
                     map.coValue.sessions[node.ownSessionID]!.lastSignature!,
             },
@@ -255,7 +258,6 @@ test("After subscribing, node sends own known state and new txs to peer", async
                         ],
                     },
                 ],
-                lastHash: map.coValue.sessions[node.ownSessionID]!.lastHash!,
                 lastSignature:
                     map.coValue.sessions[node.ownSessionID]!.lastSignature!,
             },
@@ -288,7 +290,6 @@ test("After subscribing, node sends own known state and new txs to peer", async
                         ],
                     },
                 ],
-                lastHash: map.coValue.sessions[node.ownSessionID]!.lastHash!,
                 lastSignature:
                     map.coValue.sessions[node.ownSessionID]!.lastSignature!,
             },
@@ -368,7 +369,6 @@ test("Client replies with known new content to tellKnownState from server", asyn
                         ],
                     },
                 ],
-                lastHash: map.coValue.sessions[node.ownSessionID]!.lastHash!,
                 lastSignature:
                     map.coValue.sessions[node.ownSessionID]!.lastSignature!,
             },
@@ -472,7 +472,6 @@ test("No matter the optimistic known state, node respects invalid known state me
                         ],
                     },
                 ],
-                lastHash: map.coValue.sessions[node.ownSessionID]!.lastHash!,
                 lastSignature:
                     map.coValue.sessions[node.ownSessionID]!.lastSignature!,
             },
@@ -576,7 +575,6 @@ test("If we add a server peer, all updates to all coValues are sent to it, even
                         ],
                     },
                 ],
-                lastHash: map.coValue.sessions[node.ownSessionID]!.lastHash!,
                 lastSignature:
                     map.coValue.sessions[node.ownSessionID]!.lastSignature!,
             },
@@ -1123,5 +1121,3 @@ function admStateEx(adminID: AccountID) {
         id: adminID,
     };
 }
-
-
diff --git a/src/sync.ts b/src/sync.ts
index 2241806c5..c99b01bc2 100644
--- a/src/sync.ts
+++ b/src/sync.ts
@@ -52,8 +52,6 @@ export type NewContentMessage = {
 export type SessionNewContent = {
     after: number;
     newTransactions: Transaction[];
-    // TODO: is lastHash needed here?
-    lastHash: Hash;
     lastSignature: Signature;
 };
 export type DoneMessage = {
@@ -426,7 +424,7 @@ export class SyncManager {
             const success = coValue.tryAddTransactions(
                 sessionID,
                 newTransactions,
-                newContentForSession.lastHash,
+                undefined,
                 newContentForSession.lastSignature
             );