This is the second patch of the 1.2.0 release with a few fixed regressions and a couple of improvements to dependency support. For details you can check the blog post . Make sure to check it out and post any issues you might find at GitHub.
The full changelog is here: Release 1.2.2 · crystal-lang/crystal · GitHub
Binary releases should be available in the usual channels, or arrive shortly. Check Install - The Crystal Programming Language for installation instructions.