Android Question windowOptOutEdgeToEdgeEnforcement not found

[apti]

I updated to the 13.4 b4x and now all my apps do not work. Fortunately they all give the same error.

Linking resources Error
res\values-v20\theme.xml:6: error: style attribute 'android:attr/
windowOptOutEdgeToEdgeEnforcement' not found.
error: failed linking references.

This sort of thing should not happen simply from an upgrade but clearly it does. Now my question is obvious, how do I fix this?

 

[Erel]

Now my question is obvious, how do I fix this?

The obvious answer - follow the installation instructions: https://www.b4x.com/b4a.html