diff --git a/ts/services/storageRecordOps.ts b/ts/services/storageRecordOps.ts
index 81c1e30b3daf..fa2cb7411320 100644
--- a/ts/services/storageRecordOps.ts
+++ b/ts/services/storageRecordOps.ts
@@ -888,7 +888,10 @@ export async function mergeGroupV1Record(
   });
 
   conversation.setMuteExpiration(
-    getTimestampFromLong(groupV1Record.mutedUntilTimestamp),
+    getTimestampFromLong(
+      groupV1Record.mutedUntilTimestamp,
+      Number.MAX_SAFE_INTEGER
+    ),
     {
       viaStorageServiceSync: true,
     }
@@ -1025,7 +1028,10 @@ export async function mergeGroupV2Record(
   });
 
   conversation.setMuteExpiration(
-    getTimestampFromLong(groupV2Record.mutedUntilTimestamp),
+    getTimestampFromLong(
+      groupV2Record.mutedUntilTimestamp,
+      Number.MAX_SAFE_INTEGER
+    ),
     {
       viaStorageServiceSync: true,
     }
@@ -1265,7 +1271,10 @@ export async function mergeContactRecord(
   }
 
   conversation.setMuteExpiration(
-    getTimestampFromLong(contactRecord.mutedUntilTimestamp),
+    getTimestampFromLong(
+      contactRecord.mutedUntilTimestamp,
+      Number.MAX_SAFE_INTEGER
+    ),
     {
       viaStorageServiceSync: true,
     }
diff --git a/ts/sql/migrations/1310-muted-fixup.ts b/ts/sql/migrations/1310-muted-fixup.ts
new file mode 100644
index 000000000000..63879cbd1ab3
--- /dev/null
+++ b/ts/sql/migrations/1310-muted-fixup.ts
@@ -0,0 +1,40 @@
+// Copyright 2025 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+import type { LoggerType } from '../../types/Logging';
+import { sql } from '../util';
+import type { WritableDB } from '../Interface';
+
+export const version = 1310;
+
+// Value from ts/util/timestamp.ts at the time of creation of this migration
+const MAX_SAFE_DATE = 8640000000000000;
+
+export function updateToSchemaVersion1310(
+  currentVersion: number,
+  db: WritableDB,
+  logger: LoggerType
+): void {
+  if (currentVersion >= 1310) {
+    return;
+  }
+
+  db.transaction(() => {
+    const [query, params] = sql`
+      UPDATE conversations
+        SET json = json_replace(
+          json,
+          '$.muteExpiresAt',
+          9007199254740991 -- max safe integer
+        )
+        WHERE json ->> '$.muteExpiresAt' IS ${MAX_SAFE_DATE};
+    `;
+    const { changes } = db.prepare(query).run(params);
+    if (changes !== 0) {
+      logger.warn(`updateToSchemaVersion1310: fixed ${changes} conversations`);
+    }
+
+    db.pragma('user_version = 1310');
+  })();
+
+  logger.info('updateToSchemaVersion1310: success!');
+}
diff --git a/ts/sql/migrations/index.ts b/ts/sql/migrations/index.ts
index 7e3acce1f340..15d879db3689 100644
--- a/ts/sql/migrations/index.ts
+++ b/ts/sql/migrations/index.ts
@@ -106,10 +106,11 @@ import { updateToSchemaVersion1260 } from './1260-sync-tasks-rowid';
 import { updateToSchemaVersion1270 } from './1270-normalize-messages';
 import { updateToSchemaVersion1280 } from './1280-blob-unprocessed';
 import { updateToSchemaVersion1290 } from './1290-int-unprocessed-source-device';
+import { updateToSchemaVersion1300 } from './1300-sticker-pack-refs';
 import {
-  updateToSchemaVersion1300,
+  updateToSchemaVersion1310,
   version as MAX_VERSION,
-} from './1300-sticker-pack-refs';
+} from './1310-muted-fixup';
 import { DataWriter } from '../Server';
 
 function updateToSchemaVersion1(
@@ -2087,6 +2088,7 @@ export const SCHEMA_VERSIONS = [
   updateToSchemaVersion1290,
 
   updateToSchemaVersion1300,
+  updateToSchemaVersion1310,
 ];
 
 export class DBVersionFromFutureError extends Error {
diff --git a/ts/test-node/sql/migration_1310_test.ts b/ts/test-node/sql/migration_1310_test.ts
new file mode 100644
index 000000000000..ed6529ae5ed3
--- /dev/null
+++ b/ts/test-node/sql/migration_1310_test.ts
@@ -0,0 +1,80 @@
+// Copyright 2025 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import { type WritableDB } from '../../sql/Interface';
+import { createDB, updateToVersion, insertData, getTableData } from './helpers';
+
+describe('SQL/updateToSchemaVersion1310', () => {
+  let db: WritableDB;
+
+  afterEach(() => {
+    db.close();
+  });
+
+  beforeEach(() => {
+    db = createDB();
+    updateToVersion(db, 1300);
+  });
+
+  it('leaves absent muteExpiresAt untouched', () => {
+    const convos = [
+      {
+        id: 'convo',
+        expireTimerVersion: 1,
+        json: {},
+      },
+    ];
+    insertData(db, 'conversations', convos);
+    updateToVersion(db, 1310);
+
+    assert.deepStrictEqual(getTableData(db, 'conversations'), convos);
+  });
+
+  it('leaves regular muteExpiresAt untouched', () => {
+    const convos = [
+      {
+        id: 'convo',
+        expireTimerVersion: 1,
+        json: {
+          muteExpiresAt: 123,
+        },
+      },
+      {
+        id: 'convo-2',
+        expireTimerVersion: 1,
+        json: {
+          muteExpiresAt: 8640000000000000 - 1,
+        },
+      },
+    ];
+    insertData(db, 'conversations', convos);
+    updateToVersion(db, 1310);
+
+    assert.deepStrictEqual(getTableData(db, 'conversations'), convos);
+  });
+
+  it('promotes MAX_SAFE_DATE to MAX_SAFE_INTEGER', () => {
+    insertData(db, 'conversations', [
+      {
+        id: 'convo',
+        expireTimerVersion: 1,
+        json: {
+          muteExpiresAt: 8640000000000000,
+        },
+      },
+    ]);
+    updateToVersion(db, 1310);
+
+    assert.deepStrictEqual(getTableData(db, 'conversations'), [
+      {
+        id: 'convo',
+        expireTimerVersion: 1,
+        json: {
+          muteExpiresAt: Number.MAX_SAFE_INTEGER,
+        },
+      },
+    ]);
+  });
+});
diff --git a/ts/util/timestampLongUtils.ts b/ts/util/timestampLongUtils.ts
index 5196b200fefe..7bc386b0fbd5 100644
--- a/ts/util/timestampLongUtils.ts
+++ b/ts/util/timestampLongUtils.ts
@@ -19,7 +19,10 @@ export function getSafeLongFromTimestamp(
   return Long.fromNumber(timestamp);
 }
 
-export function getTimestampFromLong(value?: Long | null): number {
+export function getTimestampFromLong(
+  value?: Long | null,
+  maxValue = MAX_SAFE_DATE
+): number {
   if (!value || value.isNegative()) {
     return 0;
   }
@@ -27,7 +30,7 @@ export function getTimestampFromLong(value?: Long | null): number {
   const num = value.toNumber();
 
   if (num > MAX_SAFE_DATE) {
-    return MAX_SAFE_DATE;
+    return maxValue;
   }
 
   return num;