I've encountered with strange behavior of Zabbix after updating to version 2.2.11. I monitor many D-Link DFL firewalls (made by Clavister by the way) via SNMP. Three years ago I created template with trigger with condition like this: {D-Link DFL:dfl210SysCpuLoad.nodata(15m)}=1 where dfl210SysCpuLoad is SNMP item key.
So, if I can not get the value of this item 15 minutes then trigger is activated. It was working fine during last three years. And than I updated Zabbix to a new version
Now some devices are monitored as they should, but some are not. On these devices when the data is not collected some items (not all!) became Unsupported with error Timeout while connecting.
Therefore trigger goes to condition Unknown with error Cannot evaluate function "D-Link DFL:dfl210SysCpuLoad.nodata(15m)": item is not supported.
Maybe with new version something was changed? Or this is a usual error with update and I should recreate corrupted devices in Zabbix?
So, if I can not get the value of this item 15 minutes then trigger is activated. It was working fine during last three years. And than I updated Zabbix to a new version

Now some devices are monitored as they should, but some are not. On these devices when the data is not collected some items (not all!) became Unsupported with error Timeout while connecting.
Therefore trigger goes to condition Unknown with error Cannot evaluate function "D-Link DFL:dfl210SysCpuLoad.nodata(15m)": item is not supported.
Maybe with new version something was changed? Or this is a usual error with update and I should recreate corrupted devices in Zabbix?