Hello,
We have just merged a PR that cleans up a bunch of deprecated methods from core [1]. Some of these have been marked for removal as far back as Foreman 2.5, although we haven’t been doing a great job of actually removing them when we say we will in the past. While we tried to open some PRs to fix the deprecated behaviors in various plugins before merging it, some plugins may still break, especially if you have any custom plugins that are outside of the foreman organization.
Plugin maintainers should take a look at the removed methods and make sure that their plugins have been updated accordingly.
Please try to notice deprecation messages in your plugins and fix the deprecated behaviors before they are removed in core in the future.