diff --git a/src/components/left/main/LeftMainHeader.tsx b/src/components/left/main/LeftMainHeader.tsx
index d9c9aa219..97eb792d9 100644
--- a/src/components/left/main/LeftMainHeader.tsx
+++ b/src/components/left/main/LeftMainHeader.tsx
@@ -11,10 +11,11 @@ import {
 } from '../../../config';
 import { IS_SINGLE_COLUMN_LAYOUT } from '../../../util/environment';
 import buildClassName from '../../../util/buildClassName';
-import { isChatArchived } from '../../../modules/helpers';
 import { formatDateToString } from '../../../util/dateFormat';
-import { selectTheme } from '../../../modules/selectors';
 import switchTheme from '../../../util/switchTheme';
+import { setPermanentWebVersion } from '../../../util/permanentWebVersion';
+import { selectTheme } from '../../../modules/selectors';
+import { isChatArchived } from '../../../modules/helpers';
 import useLang from '../../../hooks/useLang';
 import { disableHistoryBack } from '../../../hooks/useHistoryBack';
 
@@ -54,7 +55,6 @@ const ANIMATION_LEVEL_OPTIONS = [0, 1, 2];
 const PRODUCTION_HOSTNAME = 'web.telegram.org';
 const LEGACY_VERSION_URL = 'https://web.telegram.org/?legacy=1';
 const WEBK_VERSION_URL = 'https://web.telegram.org/k/';
-const PERMANENT_VERSION_KEY = 'kz_version';
 
 const LeftMainHeader: FC<OwnProps & StateProps> = ({
   content,
@@ -158,7 +158,7 @@ const LeftMainHeader: FC<OwnProps & StateProps> = ({
   }, [animationLevel, setSettingOption]);
 
   const handleSwitchToWebK = () => {
-    localStorage.setItem(PERMANENT_VERSION_KEY, JSON.stringify('K'));
+    setPermanentWebVersion('K');
     disableHistoryBack();
   };
 
diff --git a/src/modules/actions/ui/initial.ts b/src/modules/actions/ui/initial.ts
index 7b82d1fd9..55e7c30b5 100644
--- a/src/modules/actions/ui/initial.ts
+++ b/src/modules/actions/ui/initial.ts
@@ -8,6 +8,7 @@ import { setLanguage } from '../../../util/langProvider';
 import switchTheme from '../../../util/switchTheme';
 import { selectTheme } from '../../selectors';
 import { startWebsync } from '../../../util/websync';
+import { ensurePermanentWebVersion } from '../../../util/permanentWebVersion';
 
 const HISTORY_ANIMATION_DURATION = 450;
 
@@ -28,7 +29,10 @@ addReducer('init', (global) => {
   document.body.classList.add('initial');
   document.body.classList.add(`animation-level-${animationLevel}`);
   document.body.classList.add(IS_TOUCH_ENV ? 'is-touch-env' : 'is-pointer-env');
+
   switchTheme(theme, animationLevel === ANIMATION_LEVEL_MAX);
+
+  ensurePermanentWebVersion();
   startWebsync();
 
   if (IS_IOS) {
diff --git a/src/util/permanentWebVersion.ts b/src/util/permanentWebVersion.ts
new file mode 100644
index 000000000..ecf2c90cb
--- /dev/null
+++ b/src/util/permanentWebVersion.ts
@@ -0,0 +1,27 @@
+const PERMANENT_VERSION_KEY = 'kz_version';
+const AVAILABLE_VERSIONS = ['Z', 'K'] as const;
+const DEFAULT_VERSION = 'Z';
+
+export function setPermanentWebVersion(version: typeof AVAILABLE_VERSIONS[number]) {
+  localStorage.setItem(PERMANENT_VERSION_KEY, JSON.stringify(version));
+}
+
+export function ensurePermanentWebVersion() {
+  if (!hasPermanentWebVersion()) {
+    setPermanentWebVersion(DEFAULT_VERSION);
+  }
+}
+
+function hasPermanentWebVersion() {
+  const json = localStorage.getItem(PERMANENT_VERSION_KEY);
+  if (!json) {
+    return false;
+  }
+
+  try {
+    const version = JSON.parse(json);
+    return AVAILABLE_VERSIONS.includes(version);
+  } catch (err) {
+    return false;
+  }
+}