Hello.
During major upgrade of zabbix, for example, from version 5.0 to 5.2, it is necessary to upgrade the zabbix server and zabbix proxy. If, for some reason, you update the server, but not update the proxy, then what could it threaten - no data will come from the proxy to the server, or some more serious consequences for the server are possible. I heard the opinion that due to the fact that the database schema on the server will change and the database schema on the proxy will not change, it is possible that the proxy will break the database on the server.
During major upgrade of zabbix, for example, from version 5.0 to 5.2, it is necessary to upgrade the zabbix server and zabbix proxy. If, for some reason, you update the server, but not update the proxy, then what could it threaten - no data will come from the proxy to the server, or some more serious consequences for the server are possible. I heard the opinion that due to the fact that the database schema on the server will change and the database schema on the proxy will not change, it is possible that the proxy will break the database on the server.