As part of my investigations into my failing update problem I have been looking at the wp-config.php file. This file remains intact after using the migration plugin, and it is also recommended to keep it in place when doing a manual upgrade. But it can contain some extra settings that create some unusual effects.
For example, my failed upgrades would often leave large undeleted folders of installation files in the uploads folder. I have now found that I have this line in many of my sites and this explains why…
Some sites weren’t auto-updating and I found I had directives in there (I don’t know where they came from) that disabled them.
I also have these settings and I have no idea what they do:
I’m not sure if this is related to my particular issue, but it does make me wonder whether it might be good practice to make a point of using the clean sample config that comes with CP… just adding in the database name, username, password and db prefix.