Hello/Hi/Greetings,

I am trying to upgrade and getting this error:
Strict Standards: Non-static method updates::upgrade_to() should not be called statically in /gallery/admin/updates_pwg.php on line 137

I had version 2.5.1 and the upgrade to 2.5.6 worked, but it also had errors (that i didnt copy unfortunately), but still shows 2.5.6 as the version.

No matter what I've tried it will only give that error and stay on version 2.5.6, upgrade will not work. Any ideas?

Piwigo version: 2.5.6
Operating system: Linux
PHP: 5.4.37  [2015-03-22 19:08:11]
MySQL: 5.1.56-log [2015-03-22 19:08:11]
Graphics Library: ImageMagick 6.6.9-7
Piwigo URL: http://maddiegw.com/gallery