Older agents from Zabbix 1.0, Zabbix 1.1.x, Zabbix 1.4.x, Zabbix 1.6.x and Zabbix 1.8.x can still be used with Zabbix 2.0. It does not require any configuration changes on agent side.
However, to take full advantage of new and improved items, improved performance and reduced memory usage, use the latest 2.0 agent.
Only Zabbix 2.0 proxies may be used with Zabbix server. Zabbix 1.6 and 1.8 proxies are not supported with Zabbix 2.0 server.
Zabbix 2.0 proxies may only be used with Zabbix 2.0 server. They will not work with 1.8 or older Zabbix server.
All distributed monitoring nodes must be of the same major version. 1.8 nodes are not supported together with 2.0 nodes.
XML files, exported with 1.8, are supported for import in Zabbix 2.0.