Hi @langesmalle,
Another user had an applicability problem running a Katello 3.14.1 as well. Running this command seemed to fix all of his problems: Katello 3.15 doesn't show available package updates anymore
If you get an error when running it, try these steps first: Katello 3.15 doesn't show available package updates anymore
Just a disclaimer, there are other fixes for applicability in that thread but they won’t apply to your server since your running an older Katello + Pulp setup.