zstd is a newer addition (if 5 years counts as newer) to the deb package format which in the mean time made its way into stable/LTS distributions.

Unfortunately fpm chokes on these packages with:

Invalid package configuration: Unknown compression type 'zst' for control.tar in deb source package foo.deb {:level=>:error}

This makes the effing package management in this instance a tad more difficult to use. zstd is supported for both control and data archives after taking a peek with ar x.