Google hardcodes expiration dates into older apps. If you get a prompt blocking you from watching videos, you may need to clear the app data in your settings or accept that the specific version has been server-blocked.

Tap at the bottom right and wait for the process to complete. Troubleshooting Common Errors "Parse Error: There was a problem parsing the package"

You do not need to throw away a perfectly functional tablet or phone just because the native app is dead. There are several safe, verified workarounds to stream YouTube content on older software. Use a Lightweight Mobile Web Browser