For users running Android 4.2.2 (Jelly Bean) , running the latest version of the official Telegram app is no longer possible as modern versions typically require Android 6.0 or higher
Before downloading the APK, you must allow your device to install apps from outside the Play Store: telegram apk for android 4.2.2
No. It simply means you cannot use the latest version of the app. You must sideload an older version of the application using an APK file. For users running Android 4