问题
I attempted to upgrade from joomla 2.5.11 to 3.2.3 which is latest right now. First of all I checked and upgraded all extensions - CB, k2, kunena, xmap (I did not upgrade xmap as I got errors so I left it, little one not important) to latest by going extensions manager -> update tab. Then going components-> joomla-> update update to 3.2.3. The update finished but I got an error about remember.php and could not access admin panel.
Getting suggestions from Fatal error when updating joomla from 3.1.1 to 3.2.2 , I uploaded a joomla 3.2.3 package's remember.php file in /plugins/system/remember/ folder backing up previous file.
But I got another error -
Fatal error: Call to undefined method RuntimeException::get() in /home/techhe97/public_html/libraries/joomla/error/error.php on line 797
So, can't access admin panel all the way.
来源：https://stackoverflow.com/questions/22940409/errors-while-upgrading-joomla-2-5-to-3-x-x