Zabbix agents starting with version 1.4 are compatible with Zabbix 5.0. However, you may need to review the configuration of older agents as some parameters have changed, for example, parameters related to logging for versions before 3.0.
To take full advantage of new and improved items, improved performance and reduced memory usage, use the latest 5.0 agent.
Note that Zabbix agent newer than 5.0 cannot be used with Zabbix server 5.0.
Zabbix 5.0.x server can only work with Zabbix 5.0.x proxies. Zabbix 5.0.x proxies can only work with Zabbix 5.0.x server.
It is no longer possible to start the upgraded server and have older, yet unupgraded proxies report data to a newer server. This approach, which was never recommended nor supported by Zabbix, now is officially disabled, as the server will ignore data from unupgraded proxies. For more information, see the upgrade procedure.
Warnings about using incompatible Zabbix daemon versions are logged.
XML files, exported with 1.8, 2.0, 2.2, 2.4, 3.0, 3.2, 3.4, 4.0, 4.2 and 4.4 are supported for import in Zabbix 5.0.
In Zabbix 1.8 XML export format, trigger dependencies are stored by name only. If there are several triggers with the same name (for example, having different severities and expressions) that have a dependency defined between them, it is not possible to import them. Such dependencies must be manually removed from the XML file and re-added after import.