Ooor... you just upgrade your library versions. Backporting fixes is something you do as a distro maintainer to avoid having to update each application separate

Ooor... you just upgrade your library versions. Backporting fixes is something you do as a distro maintainer to avoid having to update each application separately. It almost never makes sense as a thing to do as an application author. If you find yourself in a position where you don't want to upgrade to the version being maintained by upstream then you're in trouble anyway.