Here are a few bits of information I collected at PHP Forum (Nov 9 & 10, 2005):
- It is estimated than no more than 5% of the servers running PHP have switched to PHP 5 yet
- PHP 5.0 is a feature release, not a performance release. Therefore it is slower than PHP 4.x. Therefore it makes no sense running apps designed for PHP 4 on PHP 5.0.
- PHP 5.1 should almost match the performance of PHP 4.4
- Rasmus will probably migrate Yahoo's servers from PHP 4 to PHP 5 once PHP 5.1 has undergone a few weeks without any major issue.
- It is extremely painful for everyone to make code that works on PHP 5 as well as PHP 4, especially because you cannot redefine the
clonestatement in PHP 4 for compatibility.
Okay, that’s all I can recall right now! :P
Comments from long ago:
Comment from: Harry Fuecks
“It is extremely painful for everyone to make code that works on PHP 5 as well as PHP 4, especially because you cannot redefine the clone statement in PHP 4 for compatibility”
Not sure clone is such a big problem (see links below). More of a pain is rewriting code to cope with reference issues see http://phplens.com/phpeverywhere/?q=node/view/214
Comment from: François Planque
Oh sure there is a workaround, but you gotta admit… it feels really dirty doesn’t it? :>