php 5.3 to 5.6 HELP!

Thanks.

Turns out the whole problem was one line in Common.php which both assigned a value to an array and returned the array, all in one line. Assigned it in one line, returned in the next and the problem disappeared.

We're on ancient CI v 1.0. Is there a way to upgrade to 2.2.0 in one step, or do I have to go through all the intermediate upgrades?

Cheers