I noticed when upgrading my existing 15.x installation to 15.12, the installer doesn't correctly detect the port if it is commented out in my postgresql.conf file. Instead it seems to pull in the entire contents of the postgresql.conf file:

I have to uncomment the port in the postgresql.conf file in order for the installer to correctly detect it. The installer should detect if I'm using the default port when upgrading. This is also the first time I've run into this issue when upgrading an installation using the EDB installer. Previous versions seemed to handle this situation correctly.