Version 3.0 is required and you are running 2.5.1 (Build: 20130708)
I installed 3.4???
You can't upgrade from 2.5 straight to 3.4.
Make sure you read the upgrade instructions!!
In particular - https://docs.moodle.org/34/en/Upgrading#Check_the_requirements
and - https://docs.moodle.org/30/en/Upgrading#Check_the_requirements
Be very careful you don't trip up with other server component versions as you upgrade. For example, 2.5 will not run with PHP7. Moodle 3.0.1 is fine with it. Moodle 3.4 requires it. So you will, at least have to upgrade PHP at the right moment.
Thank you
I did as you said, I upgraded to 3.0 and then to 3.4 The upgrade was successful and I got to the plugin update step and when I clicked the plugin update I got an error 500
I am stuck.
The main page also gives an error 500
System administration also gives 500 error
And into the internal address of courses I can manage to enter.
You need to check your web server's error log to find out what is causing the error 500
If you have optional plugins in the Moodle code, either take them out or make sure they are compatible with 3.4. You don't need the user interface to do that. If they are the *same* plugins as you had in 2.5 then they are NOT compatible. There have been some significant API changes since then.
There's an error log somewhere.
Error 500 tells you nothing. But a more helpful version will be in the log. If you don't see the Error 500 logged (at least) you haven't found it yet.
If you start again, how do you know you aren't going to run into the same problem? Seeing as you don't even know what the problem is?
If you read Debugging you can get more information. You can copy the debugging lines from config-dist.php to config.php and uncomment them.
However, it's very unlikely that the Error 500 was not logged *anywhere*. You would need to tell us what operating system you are running and what web server. Personally I would go back to your server admin. A server that throws an Error 500 and does not log it is not set up properly.
Pardon interruption ... Howard is quite capable in assisting, but thought this might help ...
Suggestion ... sometimes one can get directly to an admin area by using a URL upon initial access to the server.
Without trying to login, go to:
https://yoursite/admin/settings.php?section=debugging
replacing 'yoursite' above with your server URL.
That should prompt you to login and then forward you to the page for turning on debugging.
Once that's done, click on Site Admin menu link.
Catch 22 ... if your moodle is in the middle of a failed upgrade ... the above suggestion might not work.
It's the only way I know of without ssh cli access to server or cPanel text editor where one could edit the config.php file to put server in debug mode.
Best of luck!
'spirit of sharing', Ken