On the Professional PHP blog today, there's a new post with a look at backwards compatibility and the adoption of PHP5 throughout web hosting services.

I blogged about PHP 5 adoption in january when a survey put the adoption rate at 1.5%. I ran across a thread at web hosting talk, which asks PHP5 rare, why? Bugs, backward compatibility problems, and the difficulty of running two versions at once come up as issues.

I'm afraid that there are probably other BC breaks in 5.1. (Otherwise, its looking like a very nice release.)

Even more promising was some of the preliminary discussion around PHP 6.0.

He mentions some of the errors that he's noticed already under PHP 5.1, including an error reassigning $this...