There is a release candidate for 0.12.21 at https://ohse.de/uwe/testing/lrzsz-0.12.21rc.tar.gz
Please import this. The version string 0.12.21rc is greater than 0.12.21, so it should be fine to import the rc without changing the version string. Also, please be more careful with claiming people were dead. You can see current activity at https://github.com/UweOhse/
