diff --git a/lib/shared/state-sync/current-user-state-sync-spec.js b/lib/shared/state-sync/current-user-state-sync-spec.js
--- a/lib/shared/state-sync/current-user-state-sync-spec.js
+++ b/lib/shared/state-sync/current-user-state-sync-spec.js
@@ -4,13 +4,8 @@
 
 import type { StateSyncSpec } from './state-sync-spec.js';
 import type { AppState } from '../../types/redux-types';
-import {
-  type CurrentUserInfo,
-  currentUserInfoValidator,
-} from '../../types/user-types.js';
-import { convertClientIDsToServerIDs } from '../../utils/conversion-utils.js';
+import { type CurrentUserInfo } from '../../types/user-types.js';
 import { hash } from '../../utils/objects.js';
-import { ashoatKeyserverID } from '../../utils/validation-utils.js';
 
 export const currentUserStateSyncSpec: StateSyncSpec<
   CurrentUserInfo,
@@ -18,13 +13,6 @@
   void,
 > = Object.freeze({
   hashKey: 'currentUserInfo',
-  convertClientToServerInfos(info: CurrentUserInfo) {
-    return convertClientIDsToServerIDs(
-      ashoatKeyserverID,
-      currentUserInfoValidator,
-      info,
-    );
-  },
   findStoreInconsistencies() {
     return undefined;
   },
diff --git a/lib/shared/state-sync/entries-state-sync-spec.js b/lib/shared/state-sync/entries-state-sync-spec.js
--- a/lib/shared/state-sync/entries-state-sync-spec.js
+++ b/lib/shared/state-sync/entries-state-sync-spec.js
@@ -2,13 +2,11 @@
 
 import _isEqual from 'lodash/fp/isEqual.js';
 import { createSelector } from 'reselect';
-import t from 'tcomb';
 
 import type { StateSyncSpec } from './state-sync-spec.js';
 import {
   type CalendarQuery,
   type RawEntryInfos,
-  rawEntryInfoValidator,
   type RawEntryInfo,
 } from '../../types/entry-types.js';
 import type { AppState } from '../../types/redux-types.js';
@@ -19,11 +17,10 @@
 import type { ProcessServerRequestAction } from '../../types/request-types.js';
 import { actionLogger } from '../../utils/action-logger.js';
 import { getConfig } from '../../utils/config.js';
-import { convertClientIDsToServerIDs } from '../../utils/conversion-utils.js';
 import { values, combineUnorderedHashes, hash } from '../../utils/objects.js';
 import { generateReportID } from '../../utils/report-utils.js';
 import { sanitizeActionSecrets } from '../../utils/sanitization.js';
-import { ashoatKeyserverID, tID } from '../../utils/validation-utils.js';
+import { ashoatKeyserverID } from '../../utils/validation-utils.js';
 import {
   filterRawEntryInfosByCalendarQuery,
   serverEntryInfosObject,
@@ -40,21 +37,6 @@
     deleteKey: 'deleteEntryIDs',
     rawInfosKey: 'rawEntryInfos',
   },
-  convertClientToServerInfos(
-    infos: RawEntryInfos,
-    calendarQuery: CalendarQuery,
-  ) {
-    const filteredEntryInfos = filterRawEntryInfosByCalendarQuery(
-      serverEntryInfosObject(values(infos)),
-      calendarQuery,
-    );
-
-    return convertClientIDsToServerIDs(
-      ashoatKeyserverID,
-      t.dict(tID, rawEntryInfoValidator),
-      filteredEntryInfos,
-    );
-  },
   findStoreInconsistencies(
     action: ProcessServerRequestAction,
     beforeStateCheck: RawEntryInfos,
diff --git a/lib/shared/state-sync/state-sync-spec.js b/lib/shared/state-sync/state-sync-spec.js
--- a/lib/shared/state-sync/state-sync-spec.js
+++ b/lib/shared/state-sync/state-sync-spec.js
@@ -12,10 +12,6 @@
     +rawInfosKey: string,
     +additionalDeleteCondition?: Info => boolean,
   },
-  +convertClientToServerInfos: (
-    infos: Infos,
-    calendarQuery: CalendarQuery,
-  ) => Infos,
   +findStoreInconsistencies: (
     action: ProcessServerRequestAction,
     beforeStateCheck: Infos,
diff --git a/lib/shared/state-sync/threads-state-sync-spec.js b/lib/shared/state-sync/threads-state-sync-spec.js
--- a/lib/shared/state-sync/threads-state-sync-spec.js
+++ b/lib/shared/state-sync/threads-state-sync-spec.js
@@ -2,7 +2,6 @@
 
 import _isEqual from 'lodash/fp/isEqual.js';
 import { createSelector } from 'reselect';
-import t from 'tcomb';
 
 import type { StateSyncSpec } from './state-sync-spec.js';
 import type { AppState } from '../../types/redux-types.js';
@@ -14,15 +13,13 @@
 import {
   type RawThreadInfos,
   type RawThreadInfo,
-  rawThreadInfoValidator,
 } from '../../types/thread-types.js';
 import { actionLogger } from '../../utils/action-logger.js';
 import { getConfig } from '../../utils/config.js';
-import { convertClientIDsToServerIDs } from '../../utils/conversion-utils.js';
 import { combineUnorderedHashes, values } from '../../utils/objects.js';
 import { generateReportID } from '../../utils/report-utils.js';
 import { sanitizeActionSecrets } from '../../utils/sanitization.js';
-import { ashoatKeyserverID, tID } from '../../utils/validation-utils.js';
+import { ashoatKeyserverID } from '../../utils/validation-utils.js';
 
 export const threadsStateSyncSpec: StateSyncSpec<
   RawThreadInfos,
@@ -35,13 +32,6 @@
     deleteKey: 'deleteThreadIDs',
     rawInfosKey: 'rawThreadInfos',
   },
-  convertClientToServerInfos(infos: RawThreadInfos) {
-    return convertClientIDsToServerIDs(
-      ashoatKeyserverID,
-      t.dict(tID, rawThreadInfoValidator),
-      infos,
-    );
-  },
   findStoreInconsistencies(
     action: ProcessServerRequestAction,
     beforeStateCheck: RawThreadInfos,
diff --git a/lib/shared/state-sync/users-state-sync-spec.js b/lib/shared/state-sync/users-state-sync-spec.js
--- a/lib/shared/state-sync/users-state-sync-spec.js
+++ b/lib/shared/state-sync/users-state-sync-spec.js
@@ -10,18 +10,12 @@
   type UserInconsistencyReportCreationRequest,
 } from '../../types/report-types.js';
 import type { ProcessServerRequestAction } from '../../types/request-types.js';
-import {
-  type UserInfo,
-  type UserInfos,
-  userInfosValidator,
-} from '../../types/user-types.js';
+import { type UserInfo, type UserInfos } from '../../types/user-types.js';
 import { actionLogger } from '../../utils/action-logger.js';
 import { getConfig } from '../../utils/config.js';
-import { convertClientIDsToServerIDs } from '../../utils/conversion-utils.js';
 import { combineUnorderedHashes, hash } from '../../utils/objects.js';
 import { generateReportID } from '../../utils/report-utils.js';
 import { sanitizeActionSecrets } from '../../utils/sanitization.js';
-import { ashoatKeyserverID } from '../../utils/validation-utils.js';
 
 export const usersStateSyncSpec: StateSyncSpec<
   UserInfos,
@@ -37,13 +31,6 @@
       return !user.username;
     },
   },
-  convertClientToServerInfos(infos: UserInfos) {
-    return convertClientIDsToServerIDs(
-      ashoatKeyserverID,
-      userInfosValidator,
-      infos,
-    );
-  },
   findStoreInconsistencies(
     action: ProcessServerRequestAction,
     beforeStateCheck: UserInfos,