backward compatibility for verification of b64 custom param

[lajit]

Old versions of nimbus and other libraries send b64 value as a string “true“. Is it possible we can make this backward compatible to allow users to send either true or “true“

[Vladimir Dzhuvinov]

Creating and maintaining an incorrect b64 / RFC 7797 implementation is a bad idea.

If you need to support the string b64 forking and source and modifying it is probably the best approach.