Upgrade von 2.5 auf 3.6.0 schlägt fehl
From Joomla! Documentation
Joomla!
3.6.0
Errors reported
If you want to upgrade from 2.5.28 to 3.6.0 you get errors like:
Notice: Undefined property: LoginController::$input in ...administrator\components\com_login\controller.php on line 36
Fatal error: Call to a member function set() on null in ...administrator\components\com_login\controller.php on line 36
Versions affected
General Information
This pertains only to Joomla! version(s): 3.6.0
What is the cause
If you upgrade from 2.5 to 3.6.0 we did not remove some old files that get now loaded bevor the new ones. This will be fixed with 3.6.1.
How to fix
Wait for 3.6.1 (released soon) or see: https://github.com/joomla/joomla-cms/pull/11282