diff --git a/keyserver/src/cron/cron.js b/keyserver/src/cron/cron.js
--- a/keyserver/src/cron/cron.js
+++ b/keyserver/src/cron/cron.js
@@ -15,7 +15,6 @@
 import { postMetrics } from './metrics.js';
 import { postLeaderboard } from './phab-leaderboard.js';
 import { updateAndReloadGeoipDB } from './update-geoip-db.js';
-import { updateIdentityReservedUsernames } from './update-identity-reserved-usernames.js';
 import { deleteOrphanedActivity } from '../deleters/activity-deleters.js';
 import { deleteExpiredCookies } from '../deleters/cookie-deleters.js';
 import { deleteOrphanedDays } from '../deleters/day-deleters.js';
@@ -86,23 +85,6 @@
         }
       },
     );
-    schedule.scheduleJob(
-      '0 5 * * *', // every day at 5:00 AM in the keyserver's timezone
-      async () => {
-        const memBefore = getOlmMemory();
-        try {
-          await updateIdentityReservedUsernames();
-        } catch (e) {
-          console.warn(
-            'encountered error while trying to update reserved usernames on ' +
-              'identity service',
-            e,
-          );
-        } finally {
-          compareAndLogOlmMemory(memBefore, 'reserved usernames cronjob');
-        }
-      },
-    );
     schedule.scheduleJob(
       '0 0 * * *', // every day at midnight in the keyserver's timezone
       async () => {
diff --git a/keyserver/src/cron/update-identity-reserved-usernames.js b/keyserver/src/cron/update-identity-reserved-usernames.js
deleted file mode 100644
--- a/keyserver/src/cron/update-identity-reserved-usernames.js
+++ /dev/null
@@ -1,27 +0,0 @@
-// @flow
-
-import { getRustAPI } from 'rust-node-addon';
-
-import type { ReservedUsernameMessage } from 'lib/types/crypto-types.js';
-
-import { fetchAllUserDetails } from '../fetchers/user-fetchers.js';
-import { signUsingOlmAccount } from '../utils/olm-utils.js';
-
-async function updateIdentityReservedUsernames(): Promise<void> {
-  const [userDetails, rustAPI] = await Promise.all([
-    fetchAllUserDetails(),
-    getRustAPI(),
-  ]);
-  const issuedAt = new Date().toISOString();
-  const reservedUsernameMessage: ReservedUsernameMessage = {
-    statement: 'Add the following usernames to reserved list',
-    payload: userDetails,
-    issuedAt,
-  };
-  const stringifiedMessage = JSON.stringify(reservedUsernameMessage);
-  const signature = await signUsingOlmAccount(stringifiedMessage);
-
-  await rustAPI.addReservedUsernames(stringifiedMessage, signature);
-}
-
-export { updateIdentityReservedUsernames };
diff --git a/keyserver/src/fetchers/user-fetchers.js b/keyserver/src/fetchers/user-fetchers.js
--- a/keyserver/src/fetchers/user-fetchers.js
+++ b/keyserver/src/fetchers/user-fetchers.js
@@ -7,7 +7,6 @@
   FUTURE_CODE_VERSION,
 } from 'lib/shared/version-utils.js';
 import type { AvatarDBContent, ClientAvatar } from 'lib/types/avatar-types.js';
-import type { UserDetail } from 'lib/types/crypto-types.js';
 import {
   undirectedStatus,
   directedStatus,
@@ -476,16 +475,6 @@
   return result.map(row => row.username);
 }
 
-async function fetchAllUserDetails(): Promise<UserDetail[]> {
-  const query = SQL`SELECT username, id FROM users`;
-  const [result] = await dbQuery(query);
-
-  return result.map(row => ({
-    username: row.username,
-    userID: row.id,
-  }));
-}
-
 async function fetchKeyserverAdminID(): Promise<?string> {
   const changeRoleExtractString = `$.${threadPermissions.CHANGE_ROLE}`;
   const query = SQL`
@@ -528,7 +517,6 @@
   fetchAllUserIDs,
   fetchUsername,
   fetchAllUsernames,
-  fetchAllUserDetails,
   fetchKnownUserInfos,
   fetchKeyserverAdminID,
   fetchUserIDForEthereumAddress,