Hello after compiling a few games on API 21 and have noticed that there is an API 23 is this worth switching to with my future projects or is it not compatible or something ?
BB2 recommends API 23. I believe the next version of BB1 will also recommend API 23. Technically, if you know what you are doing, you can change it to whatever you want and try a different API, it may work fine, but there may be issues that you will need to resolve.