Service Monitoring uses for obtaining system information from the server a client app. This application calls Zabbix Agent that is located on each monitored server.
Zabbix Agent
Monitoring service knows how to work with Zabbix Agent from version 1.x to 5.0.x.
We would recommend to use the latest LTS version, since it can increase the performance and reduce the amount of memory used. It also brings the latest security updates.
Guide to update can be found on the official website, depending on the corresponding operating system:
Zabbix Proxy
Application Zabbix Proxy aggregate data from Zabbix Agent servers, that are not available on the public IP. For example for servers for the Virtual data center (VDC).
Recommended and only supported version Zabbix Proxy is 5.0 LTS. Older versions are not working.