One of the new features of the 2.4 SELinux userspace is support for module priorities. The idea is that distributions and administrators can override a (pre)loaded SELinux policy module with another module without removing the previous module. This lower-version module will remain in the store, but will not be active until the higher-priority module is disabled or removed again.

The "old" modules (pre-2.4) are loaded with priority 100. When policy modules with the 2.4 SELinux userspace series are loaded, they get loaded with priority 400. As a result, the following message occurs:

~# semodule -i screen.pp
libsemanage.semanage_direct_install_info: Overriding screen module at lower priority 100 with module at priority 400

So unlike the previous situation, where the older module is substituted with the new one, we now have two "screen" modules loaded; the last one gets priority 400 and is active. To see all installed modules and priorities, use the --list-modules option:

~# semodule --list-modules=all | grep screen
100 screen     pp
400 screen     pp

Older versions of modules can be removed by specifying the priority:

~# semodule -X 100 -r screen