As PHP6 is around the corner and PHP5 has been released for over three years, PHP is officially discontinuing development of their 4.4.x branch at the end of this year except to patch critical security issues.
In tandem with this, the MyBB Group will be dropping support for PHP4 for the next feature release (i.e., 1.6.0 or 2.0.0) coming in 2008. Some new features that PHP5 has provided are much better OOP features, a “MySQL-Improved” extension and many new built-in functions. Many of these new features are not backwards-compatible with PHP4 which meant that the MyBB Group had to find ways to allow both versions of PHP to return the same result.
With the termination of PHP4 support, MyBB developers can fully capture and utilize the “new” (not really since PHP5 is 3 years old) features that were released in PHP5 without having to worry about backward-compatibility. Thus, the MyBB code can be more streamlined and show improved performance.
Of course this move comes with a price: MyBB users on web hosts with PHP4 will not be able to use newer versions of MyBB (after 1.4.x).
MyBB isn’t the only PHP application going in this direction. See GoPHP5 for a listing of other projects taking part in this motion.
Do you think this move is a good idea? Does your host still use PHP4? Leave your comments 
I think it’s a good move, it only only be good for MyBB, allowing it to remove redundant code supporting PHP4 and be able to use the new, improved PHP5 functions.