B4A uses signing scheme v2, 3 and 4. Make sure to use the latest version of B4A.
About certificate pinning. You made another post where you mistakenly wrote that it is important for security. This is wrong. It is not required. The whole internet is built without certificate pinning and relies on trusted authorities.
The only case where it can be important is if you are using a non-trusted certificate and you don't want to enable the "trust all" option.