Also a community report here: https://github.com/mattermost/mattermost-server/issues/15979
Binary mmctl from https://releases.mattermost.com/5.28.0/mattermost-team-5.28.0-linux-amd64.tar.gz is linked against the libc.musl-x86_64.so.1
Steps to reproduce
libc.musl-x86_64.so.1 => not found
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f647dd9c000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f647d9fd000)
This compilation was a mistake (binary for Alpine)
See description. mmctl on v5.28 should work.
Miguel tested and confirmed that the binary included in both team and enterprise releases is built correctly and from the right version tag. Closing.