The 4.2.1 update was a small update fixing an inconvenient exitcode when using
--api --get-branch and it was a change in output and some minor cosmetics.
The 4.2.2 update was a small update fixing a regression bug as reported in this post
A text constant had gone missing. I can’t remember removing it but it was gone.
This missing constant only affected situations where a country having no mirrors was specified either on commandline, in pacman-mirrors.conf or in a custom-mirrors.json.
The effect would be pacman-mirrors stalling with an error stating the constant did not exist. Adding the constant in the file removed the error.