Most distributions are not created by the main Freeciv developers, they are contributed by third parties.
Please note that we don't verify their contents; problems with these packages are better reported to the maintainer of the package.
Also check the dir link and your vendor/distributor's site; they may have more recent updates than the ones listed here.
Another option is to search for Freeciv distributions on Filewatcher or a similar search service.

Feature releases are typically not compatible with each other, i.e. a 2.1 client cannot connect to a 2.2 server.