I have not posted any thoughts recently because I am working on an amazing migration to the Cloud project and I spend most of my time there. However, recently I got in a situation which reminded me of a discussion that I had a few months ago in OTN. The discussion was related with issues that users had with loading APP files in their upgraded applications.
In my case, we were working on upgrading the applications from 126.96.36.199 to 188.8.131.52. We followed the process suggested by Oracle and we upgraded 184.108.40.206 to 220.127.116.11 and then moved the applications to 18.104.22.168. When I started testing the upgraded applications I found that in one out of the three applications it was not possible to extract and reload the extracted metadata without corrupting the application.