If you're experiencing issues with Telegram apps like wallet and blum after upgrading to version 1.2.0, including all preview versions, and you've confirmed that 1.1.0 works fine after downgrading, it's possible that the issue is related to Android System WebView. Android System WebView is a browser component that allows apps to display web content within the app itself. If there are compatibility issues with the latest version of Telegram and Android System WebView, it could cause problems with the functionality of Telegram apps. Here are some steps you can take to resolve this issue:

  1. Check for Updates: Ensure that your Android System WebView is up to date. Sometimes, developers release updates to fix compatibility issues with new app versions.
  2. Clear Cache and Data: Go to your device's settings, find Telegram in the list of apps, and clear its cache and data. This can resolve issues caused by corrupted data.
  3. Reinstall Telegram: Uninstall Telegram and then reinstall the latest version. This can help fix any installation issues that might be causing the problem.
  4. Check for Known Issues: Look for any known issues with the latest version of Telegram or Android System WebView. Sometimes, developers post information about known issues and their solutions on their official websites or social media channels.
  5. Contact Support: If none of the above steps work, consider contacting Telegram support for further assistance. They might provide specific guidance or acknowledge the issue as a known bug.
  6. Stay Updated: Keep an eye on updates for both Telegram and Android System WebView. Developers often release updates to fix bugs and improve compatibility.

By following these steps, you should be able to resolve most issues related to Telegram apps not working after upgrading to version 1.2.0. If the problem persists, it might be worth considering rolling back to an earlier version of Android or waiting for a future update that addresses this issue.