University Joomla 2.5.20 Upgrade to Joomla 3.3.3 FAIL

Hi peeps and gkpro team

Have just redesigned our website using the University template using Joomla 2.5.20 Quickstart.
Had a look at the timeline for Joomla support for 2.5 and realised that in 3 months time I will have to update to J3. So I had the bright idea of updating my current offline site now before I made it a live site that would need updating later.

There appears to be no clear guildlines on how to work this out if you don't have the option showing under Joomla Updates. For example changing the update configuration setting to Short Term Support [STS] does not bring up the new J3 update option, but even worst I have noted that I have no option to update to version 2.5.24 via the Joomla Update area.

So I did the smart things and did my full Akeeba Backup, and then spent and hour reading joomla documentation on which J3 file to use for the upgrade process. I ended up selecting the Joomla_3.3.3-Stable-Full_Package.zip version and installed (or tried to) via the Extension Installation area.

First attempt did nothing, ie after upload there was no installation process. It just showed the Extensions Installation window as if I had just clicked on the link. Second attempt it processed it and arrived at a white screen. Reloading produced a white screen with some error ending with: system/plg_gkextmenu/plg_gkextmenu.php on line 42

I couldnt get anywhere as the same page error was shown on all pages - ie nothing, so I did a restore from backup. I have also attempted to use a Joomla_3.3.3-Stable-Update_Package.tar.gz file as it is only 5.4mb which gets in under my 8mb php upload limit (have to look into this, i know). However installing this through the Extension Installer also just produces a refreshed Extension Installer page and no update at all.

Question: WTF is going on?
Real Questions:
Do I need to actually uninstall "ALL" modules that are J2.5 and then attempt the update and then reinstall Gavicks J3 modules for the update process to work?
Is there some other upgrade file I am needing to do?
Will removing all modules/extensions that are J2.5 mean that the data will remain and a new install of J3 version will pick up the old data? (only have gavick modules live and Event Booking module live)

Any other pointers would be great, cause I've seriously modified a fair bit including K2 fields and content inserted which I dont want to have to redo in a J3 Quickstart install

Thank for reading and giving me some help.

Hi,
in most cases if you have J3.3 already,
you have to re-install all:
1) GK template (must be version for J3x)
2) All GK modules
3) All GK plugins

About your customization if there were any in files, you have to remember where you done it.
So I hope that you have full back-up, of your J2.5 in case you need some files from it.

Migration is never easy. Some beginner users always hire somebody to make sure that everything will be okey.
J2.5 -> 3.3 was a big step.
Next versions will be easy to upgrade (J3.4+), I hope.

Hi Oscar

Thanks for the pointers. After spending a whole day continuously attempting different items removed from my 2.5 version, I did manage to remove enough extensions, modules and plugins to get the generic Joomla Update to show the J3.3.3 update option under STS.

It however was having only 82.6% completion on each attempt and problems with not completing the database sqls.
Accessing phpMyAdmin and disabling the plg_system_remember did allow me to log into the admin panel, but accessing anything other then k2 created controller.php line 42 error and searching for a reason or fix wasted another day.

So at 1am I installed a fresh copy of J3.3.3 and have been doing sql database inserts from my working backup. Managed to import all my menus and modules with positions recovered successfully. Now as you mentioned, I've just got to remember what an earth I customised in my J2.5 version.

Just from a point of understanding, is there much difference between the way the University template J2.5 was coded when compared to J3? I want to just copy and paste my k2 templates back in without any headaches

Also as a user of these forums, is there a reason why I cannot log into the Gavick forum area when using Chrome? I have to use anything but Chrome if I want to write a reply. Reading and Viewing posts is ok as long as I'm not logged in. As soon as I am logged in, the forum page continues to fail in loading the page.

Thanks again.