I have upgrade php version to 7.0.22 and this error happens.
Tell us which line of Common.php is causing this and what CI version are you using.
I was upgrading codeigniter application from 2.1.x to 3.1.6,
I'm receiving same error on line number: 257.
My Php version is 5.6
You need to replace your system folder. This file has been moved to system/core/Common.php, so you must be using an old version. Follow the upgrading section in the user guide.
i was facing Notice: Only variables should be passed by reference in C:\xampp\htdocs\pos\system\codeigniter\core\Common.php on line 148
i don't know how to fix it
and line no 148 is:
$objects[$class] =& instantiate_class(new $name());
$objects[$class] =& instantiate_class(new $name());
Is the same as writing:
$objects[$class] =& new $name();
Which is the way that it needed to be written to glue PHP 4 with PHP 5.3 code because it prevented strict standard warnings in PHP 5.3.
Now this can be written as:
$objects[$class] = new $name();
https://stackoverflow.com/questions/7653709/codeigniter-instantiate-class-function#answer-7653853
instantiate_class() hasn't existed in CI since version 2.0.0 ... We're at 3.1.10 now.
In case it wasn't clear when I closed the issue, @zploskey answered it appropriately - if you get this error, it means you've screwed up an update.