diff --git a/keyserver/src/socket/socket.js b/keyserver/src/socket/socket.js
--- a/keyserver/src/socket/socket.js
+++ b/keyserver/src/socket/socket.js
@@ -77,6 +77,7 @@
   fetchViewerForSocket,
   extendCookieLifespan,
   createNewAnonymousCookie,
+  isCookieMissingSignedIdentityKeysBlob,
 } from '../session/cookies.js';
 import { Viewer } from '../session/viewer.js';
 import { commitSessionUpdate } from '../updaters/session-updaters.js';
@@ -466,6 +467,9 @@
       serverRequests.push({ type: serverRequestTypes.PLATFORM_DETAILS });
     }
 
+    const isCookieMissingSignedIdentityKeysBlobPromise =
+      isCookieMissingSignedIdentityKeysBlob(viewer.cookieID);
+
     if (!sessionInitializationResult.sessionContinued) {
       const [threadsResult, entriesResult, currentUserInfo, knownUserInfos] =
         await Promise.all([
@@ -542,6 +546,15 @@
       });
     }
 
+    const signedIdentityKeysBlobMissing =
+      await isCookieMissingSignedIdentityKeysBlobPromise;
+
+    if (signedIdentityKeysBlobMissing) {
+      serverRequests.push({
+        type: serverRequestTypes.SIGNED_IDENTITY_KEYS_BLOB,
+      });
+    }
+
     if (serverRequests.length > 0 || clientResponses.length > 0) {
       // We send this message first since the STATE_SYNC triggers the client's
       // connection status to shift to "connected", and we want to make sure the