There seems to be no way to activate anyone besides an admin from entering a 2.5 Moodle.
Also, the left-hand control panel is unstable because entire blocks of commands disappear and don't come back as you select various items. No matter how much I read and click, the new user log-in NEVER has appeared once. Admin works. Guests doesn't work.
The documentation describes old and sometimes very old versions of the moodle. The location strings no longer match the control panel environment.
I had a backup from a previous version, but the new Moodle refused to restore it. An entire course lost.