Chris Shiflett has some statistics on the adoption of PHP 5 and other versions of PHP.

• PHP 4.4.2 will become the dominant version during June 2006.
• PHP 5.1.2 is now the dominant PHP 5 version.
• PHP 5 rises to 8%, and raises its adoption speed again.
• PHP 4.3.9 and older keep a marketshare of 46% this month.

There are tons of statistics and graphs on PHP usage and usage evolution on Nexen.

It seems like many people are jumping from PHP 4 straight to PHP 5.1.

Since PHP 5 adoption is getting a bit faster, it may not be long until it’s possible to use PHP 5 code in a mainstream script without worrying too much about compatibility with people on PHP 4.

The adoption of PHP 5 so far has been disappointing considering it’s been out for quite a while but I think it should be expected as many users had got used to PHP 4′s shortcomings and PHP 5 doesn’t really contain anything revolutionary.