I want to upgrade my application from slim 3 to slim 4 this year and now I see the slim5 tag on github. Is there already a roadmap for slim5?
There is no roadmap for v5 yet. There are some Slim 5 labels for ideas and changes that could warrant a v5.
Slim 5 is therefore not planned for the near future.
No, I do not think they are planning for Slim 5 in near future.