Catch missed changelog

.env

@@ -1,5 +1,5 @@
 API_ID=1025907
 API_HASH=452b0359b988148995f22ff0f4229750
 VERSION=0.8.6
-VERSION_FULL=0.8.6 (1)
+VERSION_FULL=0.8.6 (4)
-BUILD=1
+BUILD=4

src/lib/appManagers/apiUpdatesManager.ts

@@ -692,7 +692,7 @@ export class ApiUpdatesManager {
       if(newVersion) {
         this.updatesState.syncLoading.then(() => {
           fetch('changelogs/' + newVersion + '.md')
-          .then(res => res.text())
+          .then(res => (res.status === 200 && res.ok && res.text()) || Promise.reject())
           .then(text => {
             const pre = `**Telegram Web${App.suffix} was updated to version alpha ${newVersion}**\n\n`;