We still have one web-app written in perl, it's based on the mojolicious web framework to keep it somewhat maintainable, the app used to be heavily tied to mod_perl1 which has thankfully been 'modernised' to not use mod_perl1 or 2 and instead run with mojo+nginx. I expect this to continue being in service and maintained for another 1-2 years before being replaced by a python rewrite.