diff --git a/keyserver/src/shared/state-sync/current-user-state-sync-spec.js b/keyserver/src/shared/state-sync/current-user-state-sync-spec.js
new file mode 100644
--- /dev/null
+++ b/keyserver/src/shared/state-sync/current-user-state-sync-spec.js
@@ -0,0 +1,18 @@
+// @flow
+
+import type {
+  CurrentUserInfo,
+  OldCurrentUserInfo,
+} from 'lib/types/user-types.js';
+
+import type { StateSyncSpec } from './state-sync-spec.js';
+import { fetchCurrentUserInfo } from '../../fetchers/user-fetchers.js';
+import type { Viewer } from '../../session/viewer.js';
+
+export const currentUserStateSyncSpec: StateSyncSpec<
+  OldCurrentUserInfo | CurrentUserInfo,
+> = Object.freeze({
+  fetchAll(viewer: Viewer) {
+    return fetchCurrentUserInfo(viewer);
+  },
+});
diff --git a/keyserver/src/shared/state-sync/entries-state-sync-spec.js b/keyserver/src/shared/state-sync/entries-state-sync-spec.js
new file mode 100644
--- /dev/null
+++ b/keyserver/src/shared/state-sync/entries-state-sync-spec.js
@@ -0,0 +1,17 @@
+// @flow
+
+import { serverEntryInfosObject } from 'lib/shared/entry-utils.js';
+import type { CalendarQuery, RawEntryInfos } from 'lib/types/entry-types.js';
+
+import type { StateSyncSpec } from './state-sync-spec.js';
+import { fetchEntryInfos } from '../../fetchers/entry-fetchers.js';
+import type { Viewer } from '../../session/viewer.js';
+
+export const entriesStateSyncSpec: StateSyncSpec<RawEntryInfos> = Object.freeze(
+  {
+    async fetchAll(viewer: Viewer, query: $ReadOnlyArray<CalendarQuery>) {
+      const entriesResult = await fetchEntryInfos(viewer, query);
+      return serverEntryInfosObject(entriesResult.rawEntryInfos);
+    },
+  },
+);
diff --git a/keyserver/src/shared/state-sync/state-sync-spec.js b/keyserver/src/shared/state-sync/state-sync-spec.js
new file mode 100644
--- /dev/null
+++ b/keyserver/src/shared/state-sync/state-sync-spec.js
@@ -0,0 +1,12 @@
+// @flow
+
+import type { CalendarQuery } from 'lib/types/entry-types.js';
+
+import type { Viewer } from '../../session/viewer.js';
+
+export type StateSyncSpec<Infos> = {
+  +fetchAll: (
+    viewer: Viewer,
+    calendarQuery: $ReadOnlyArray<CalendarQuery>,
+  ) => Promise<Infos>,
+};
diff --git a/keyserver/src/shared/state-sync/state-sync-specs.js b/keyserver/src/shared/state-sync/state-sync-specs.js
new file mode 100644
--- /dev/null
+++ b/keyserver/src/shared/state-sync/state-sync-specs.js
@@ -0,0 +1,16 @@
+// @flow
+
+import { currentUserStateSyncSpec } from './current-user-state-sync-spec.js';
+import { entriesStateSyncSpec } from './entries-state-sync-spec.js';
+import type { StateSyncSpec } from './state-sync-spec.js';
+import { threadsStateSyncSpec } from './threads-state-sync-spec.js';
+import { usersStateSyncSpec } from './users-state-sync-spec.js';
+
+export const serverStateSyncSpecs: {
+  +[string]: StateSyncSpec<*>,
+} = Object.freeze({
+  threads: threadsStateSyncSpec,
+  entries: entriesStateSyncSpec,
+  currentUser: currentUserStateSyncSpec,
+  users: usersStateSyncSpec,
+});
diff --git a/keyserver/src/shared/state-sync/threads-state-sync-spec.js b/keyserver/src/shared/state-sync/threads-state-sync-spec.js
new file mode 100644
--- /dev/null
+++ b/keyserver/src/shared/state-sync/threads-state-sync-spec.js
@@ -0,0 +1,15 @@
+// @flow
+
+import type { StateSyncSpec } from './state-sync-spec.js';
+import {
+  fetchThreadInfos,
+  type FetchThreadInfosResult,
+} from '../../fetchers/thread-fetchers.js';
+import type { Viewer } from '../../session/viewer.js';
+
+export const threadsStateSyncSpec: StateSyncSpec<FetchThreadInfosResult> =
+  Object.freeze({
+    fetchAll(viewer: Viewer) {
+      return fetchThreadInfos(viewer);
+    },
+  });
diff --git a/keyserver/src/shared/state-sync/users-state-sync-spec.js b/keyserver/src/shared/state-sync/users-state-sync-spec.js
new file mode 100644
--- /dev/null
+++ b/keyserver/src/shared/state-sync/users-state-sync-spec.js
@@ -0,0 +1,13 @@
+// @flow
+
+import type { UserInfos } from 'lib/types/user-types.js';
+
+import type { StateSyncSpec } from './state-sync-spec.js';
+import { fetchKnownUserInfos } from '../../fetchers/user-fetchers.js';
+import type { Viewer } from '../../session/viewer.js';
+
+export const usersStateSyncSpec: StateSyncSpec<UserInfos> = Object.freeze({
+  fetchAll(viewer: Viewer) {
+    return fetchKnownUserInfos(viewer);
+  },
+});
diff --git a/keyserver/src/socket/session-utils.js b/keyserver/src/socket/session-utils.js
--- a/keyserver/src/socket/session-utils.js
+++ b/keyserver/src/socket/session-utils.js
@@ -4,10 +4,7 @@
 import t from 'tcomb';
 import type { TUnion } from 'tcomb';
 
-import {
-  serverEntryInfo,
-  serverEntryInfosObject,
-} from 'lib/shared/entry-utils.js';
+import { serverEntryInfo } from 'lib/shared/entry-utils.js';
 import type { UpdateActivityResult } from 'lib/types/activity-types.js';
 import type { IdentityKeysBlob } from 'lib/types/crypto-types.js';
 import { isDeviceType } from 'lib/types/device-types.js';
@@ -65,6 +62,7 @@
   setCookieSignedIdentityKeysBlob,
 } from '../session/cookies.js';
 import type { Viewer } from '../session/viewer.js';
+import { serverStateSyncSpecs } from '../shared/state-sync/state-sync-specs.js';
 import { activityUpdater } from '../updaters/activity-updaters.js';
 import { compareNewCalendarQuery } from '../updaters/entry-updaters.js';
 import type { SessionUpdate } from '../updaters/session-updaters.js';
@@ -392,21 +390,20 @@
   status: StateCheckStatus,
   calendarQuery: CalendarQuery,
 ): Promise<StateCheckResult> {
+  const query = [calendarQuery];
   if (status.status === 'state_validated') {
     return { sessionUpdate: { lastValidated: Date.now() } };
   } else if (status.status === 'state_check') {
     const promises = {
-      threadsResult: fetchThreadInfos(viewer),
-      entriesResult: fetchEntryInfos(viewer, [calendarQuery]),
-      currentUserInfo: fetchCurrentUserInfo(viewer),
-      userInfosResult: fetchKnownUserInfos(viewer),
+      threadsResult: serverStateSyncSpecs.threads.fetchAll(viewer, query),
+      entriesResult: serverStateSyncSpecs.entries.fetchAll(viewer, query),
+      currentUserInfo: serverStateSyncSpecs.currentUser.fetchAll(viewer, query),
+      userInfosResult: serverStateSyncSpecs.users.fetchAll(viewer, query),
     };
     const fetchedData = await promiseAll(promises);
     const hashesToCheck = {
       threadInfos: hash(fetchedData.threadsResult.threadInfos),
-      entryInfos: hash(
-        serverEntryInfosObject(fetchedData.entriesResult.rawEntryInfos),
-      ),
+      entryInfos: hash(fetchedData.entriesResult),
       currentUserInfo: hash(fetchedData.currentUserInfo),
       userInfos: hash(fetchedData.userInfosResult),
     };
diff --git a/lib/shared/entry-utils.js b/lib/shared/entry-utils.js
--- a/lib/shared/entry-utils.js
+++ b/lib/shared/entry-utils.js
@@ -12,6 +12,7 @@
   RawEntryInfo,
   EntryInfo,
   CalendarQuery,
+  RawEntryInfos,
 } from '../types/entry-types.js';
 import { calendarThreadFilterTypes } from '../types/filter-types.js';
 import type { UserInfos } from '../types/user-types.js';
@@ -224,9 +225,9 @@
   return { ...rest }; // we only do this for Flow
 }
 
-function serverEntryInfosObject(array: $ReadOnlyArray<RawEntryInfo>): {
-  +[id: string]: RawEntryInfo,
-} {
+function serverEntryInfosObject(
+  array: $ReadOnlyArray<RawEntryInfo>,
+): RawEntryInfos {
   const obj = {};
   for (const rawEntryInfo of array) {
     const entryInfo = serverEntryInfo(rawEntryInfo);