The default error message set for unsupported items was changed from “Item is not supported.” and “ZBX_NOTSUPPORTED” to “Unknown error.”. This message is used when item check fails without setting error message.
Monitoring of Windows protected processes was improved. Therefore in some cases on Windows (2008 Server and later) proc.num may return more found processes than previously.
Zabbix now tries to differentiate item timeouts from host timeouts. If another item check was successful between two failed checks of a problematic item, then the problematic item is marked as not supported after the second failed check without affecting host availability.
Item vm.memory.size[total] moved from “Filesystems” to “Memory” application in Template OS Windows.
In order to fix it, import this template from https://www.zabbix.org/wiki/Zabbix_Templates/Official_Templates.