Step 1: Enable Unknown SourcesBefore installing any APK from outside the Play Store, you must allow your device to install third-party apps. Go to Settings > Security > and toggle on "Unknown Sources."
There are several reasons why you might want to download YouTube for Android from UptoDown instead of the Google Play Store: youtube for android 41 2 uptodown upd
If you are looking to update your YouTube app on an older device using Uptodown, follow these steps: Step 1: Enable Unknown SourcesBefore installing any APK