Howard Miller

Nothing in Moodle. It's a factor of whatever file sharing you are using and the underlying server.

This probably isn't a huge problem. BUT... if you haven't done so already, it's vital that you set up a proper caching server (e.g. Redis). The default is to cache to the file area and this definitely will ruin the performance of your site.

Are you possibly following a bookmarked URL to Moodle? It may contain the id of a course that no longer exists.

I've absolutely no idea what you're asking. What's 'alt-php' and 'ea-php'?

Ok - so can you go and get that file from your system (the one in the error message) and attach it here. Let's check which version it came from.

Well... that file doesn't look like 4.2.2. That's all I can say for certain. If that file didn't get updated then you need to ask what went wrong and what other files might be wrong.

How did you copy the new files onto your server? Did you remove the old version first?