Hello Allen,
2.2.x is a version that is working on some background code rewrites in preparation for the new 3.0.0 UI which is also being worked on the side as well. The plan is to marry the two codes sets, so 2.2.x might never be released publicly but rolled into 3.0.0.

It may or may not have any noticeable benefits…depending on what you are trying to do. It can certainly be built from our build script and run. So far it seems to be stable, but it is a working code base and can and might change.

I am currently working on my imaging script that I use to build images. Once I have that done, I will likely be releasing a 2.1.3 release. That will basically be the same as 2.1.2, but with an updated kernel to support the Raspberry Pi 4, 8GB…as that came out after 2.1.2 and there have been a few that have had issues when trying to run on that particular board.

If you are up to testing 2.2.x or have a specific need to use it, let me know. If you see something that 2.1.2 doesn’t let me know, and I will let you know if the base code for 2.2.x has support for that.