From release announcemenet:
After a lengthy QA process, PHP 4.3.4 is finally out!
This is a medium size maintenance release, with a fair number of bug fixes.
All users are encouraged to upgrade to 4.3.4.
Bugfix release
PHP 4.3.4 contains, among others, following important fixes, additions
and improvements:
* Fixed disk_total_space() and disk_free_space() under FreeBSD.
* Fixed FastCGI support on Win32.
* Fixed FastCGI being unable to bind to a specific IP.
* Fixed several bugs in mail() implementation on win32.
* Fixed crashes in a number of functions.
* Fixed compile failure on MacOSX 10.3 Panther.
* Over 60 various bug fixes!
For full list of changes in PHP 4.3.4, see ChangeLog:
http://www.php.net/ChangeLog-4.php#4.3.4