With effect from March 1st 2009 Cambridge New Media Services will no longer be developing any of our Plugins to work with WordPress 2.6 or lower in effect if you are still using Wordpress 2.6 after the 1st of March and you update your CNMS plugin we do not guarantee it will work. Also a gentle reminder we currently don't support WordPress earlier then 2.5.
Likewise we are shifting most of our code base to be OO class based this allows us a lot of advantages and should reduce a very small amount of compatibility naming issues with other plugins. However this means that CNMS plugins may well be in the future PHP5 or higher so we can take full advantage of OO based code. Consequently if you are still running legacy PHP4 or worse 3 consider this advanced warning and have you thought about upgrading?
If you still convinced you should be thinking about upgrading might I point you to the gophp5 website FAQ Why should I drop PHP4 you might want to know and gives you a hint if using 4 how much of a legacy system you are using that the gophp5 site was last updated on the 5th February 2008 when they considered their job done. From our own experience we think they were premature.