It took a bit longer then originally anticipated, but PHP 5.2.1 was finally released today. Big thanks to all the people who have helped make this release possible, by reporting bugs, identifying security issues and of course helping to resolve those issues and improving the language in general.
The focus of this release was making PHP 5.2 more stable and more secure. The complete shopping list of changes can be found here. The official release announcement can be found at http://www.php.net/releases/5_2_1.php, it details the major changes and all of the security fixes that have been made in this release.
Given the significant number of security issues that were resolved, my recommendation is that all users of PHP, especially those running really old versions (You know who you are ) consider upgrading to this release as soon as possible. Not only will the security of your setup increase, but the stability and the performance of your PHP will improve as well.
Great to see another PHP release focusing on security and performance issues. On a very minor note I noticed that http://www.php.net/releases/5_2_1.php mentions dropping support for windows 98 (item 5 under 'key improvements') although I'm running 5.2.1 without problems so far on Win98 / Apache 2.2.4 for development purposes ...
The official changelog [http://www.php.net/ChangeLog-5.php#5.2.1] only mentions the stat() reimplementation in this release drops support for windows 95 (item 30).
In the last update including PHP 4.4.5.. I think there is a little error:
"Prevent search engines from indexing the phpinfo() page."
In the announcement at php.net you say this is only for php 5.2.1 but I can see this "bug" fixed in the Changelog for php 4:
"added a meta tag to phpinfo() output to prevent search engines from indexing the page."
I just upgraded our 4 web servers from 5.1.6 to 5.2.1. Everything appears to be running much faster than before. The best of all, for us, is the performance of json_encode. The built in version is 55 times faster (including calls to utf8_encode for a typical string on our server) than the version, written in PHP, that we used before. The json_encode function is called around 10 times a second per server (we have a lot of ajax functions on our site).