I have just upgraded to the latest version of Moodle 4.
I downloaded the code and unpacked it into a fresh directory. I then made sure that any plugins I was testing with Moodle 4 were copied over ´to th~eir respective directories.
I placed the old version into Maintenance Mode and then went and renamed the respective directories so that that where the old code was became Moodle old and that where the new code was now became Moodle.
Then I ran the updater. Everything went fine until I came to the part where it asked me to update the database. When I did this a white screen appeared and just plain remained.
Interestingly enough I was able to navigate back to the courses, and the dashboard, but each time I tried to access the Admin area, the white page reapeared.
So Ok, perhaps a plugin is causing an issue, but then no errors appeared when it went through the plugins check, so is there an issue with that check?
Any thoughts would be appreciated, but either way I shall wait untill the next code release and try again and see whether the issue is fixed then.