There's a movement stirring in a part of the PHP community (the PHP-FIG group) that wants to bring back the idea behind the "GoPHP5" movement years back. This time, though, their focus is a bit different - it's not switching to PHP5 they want, it's pushing towards PHP 5.5.
We all know that PHP 5.3 is about to lose even security support in the first half of next year. PHP 5.3 is still the most widely used PHP version, with the completely unsupported 5.2 a strong second [and] 5.4 hasn't even reached 10% yet, and 5.5, which is current stable, barely registers. [...] The last time this big of a chicken-and-egg issue existed was around moving to PHP 5.x at all, which took *for frickin' ever* to supplant PHP 4. [...] I believe it is time to discuss round 2 of that effort. I also believe that it would be good for FIG to play a leading role in such an effort if possible.
There's been some varied feedback on the thread both for and against. Overall, there's a lot of support for the idea, but there are a few "hitches" in the plans - mainly the lack of support from the linux OS vendors to bump up their versions. The projects themselves are receptive, many noting that they've been planning the first steps to this already - a move to PHP 5.4 only.