They are available for cPanel shared hosting services, you can select your php version through your cPanel as instructed in the link below:
http://secure.plusplushosting.net/knowledgebase/1090/Selecting-your-PHP-version-through-cPanel.html
Changelog:
- Glibc gethostbyname buffer overflow fixed
- Eliminated the ability to run arbitrary code in some cases
5.6.6 --> http://php.net/ChangeLog-5.php#5.6.6
5.5.22 --> http://php.net/ChangeLog-5.php#5.5.22
5.4.38 --> http://php.net/ChangeLog-5.php#5.4.38
- Friday, February 27, 2015