Idea Summary
Supporting hundreds of customers across decades of APEX releases has shown that all too often the previous APEX schemas from previous APEX installations have been left around in the database.

Use Case
Too many folks have a bunch of old APEX schemas hanging around.

Preferred Solution (Optional)
It would be great if there were a very simple region on the APEX homepage (maybe just in the internal workspace?) that said something along the lines of “APEX is up to date, but we have noticed that you have the following old APEX schemas in the database. If you are happy with the existing APEX 26.2 environment, these earlier versions of APEX can be removed from your database.”
APEX_260100 (remove)
APEX_240200 (remove)
APEX_240100 (remove)
APEX_05000 (remove)

The remove link could look through all USER code in the database to see if there are any references to old packages and let the admin know if there are before removing. 

If none, just remove. If some, provide a “Are you really sure, there are existing references to old versions of APEX that should be updated to not refer to a specific version of APEX or should be updated to the latest version of APEX (although we strongly recommend that you never tie your APEX calls to a specific version of APEX).” message.

Then the result of the query that found those references would be displayed:
SCHEMA, OBJECT_NAME, OBJECT_TYPE, SOURCE CODE
In the source code column, the reference to old APEX schemas would be highlighted.