The latest version of Zabbix can be downloaded from Softpedia
Zabbix 2.2 Beta 1, an enterprise-class open source distributed monitoring solution, released under the GPL (free of charge for both commercial and non-commercial use), is now out and ready for testing.The Zabbix monitoring solution has been separated into multiple branches and this latest issue is yet another stable one, featuring several changes and improvements.
According to the changelog, the overall system performance has been significantly improved thanks to the introduction of value cache for faster trigger processing, support has been implemented for monitoring of the VMWare virtualization platforms, and much more.
A complete list of changes can be found in the official changelog. Download 2.2 Beta 1 right now from Softpedia.
Remember that this is a development version and it should NOT be installed on production machines. It is intended for testing purposes only.