URI validation, introduced in Zabbix 3.4.2, now can be turned off/on in the new VALIDATE_URI_SCHEMES frontend constant.
vmware.eventlogitems that previously were always taking only the 10 latest events will now browse up to 1000 (this is a VMware limitation) events in search of events that have not yet been processed. This means there is less chance to miss events when they are generated at a higher rate. Zabbix can also catch up after some downtime.
From now on, Zabbix internal item zabbix[java,,ping] will not become not supported if java gateway is misconfigured or java gateway is unreachable.
An event will now only be deleted by the housekeeper if it is not associated with a problem in any way. This means that if an event is either a problem or recovery event, it will not be deleted until the related problem record is removed. Additionally, the housekeeper now will delete problems first and events after, to avoid potential problems with stale events or problem records.
This feature is experimental. Zabbix has recently started to support storage of historical data by means of Elasticsearch instead of a database. For more information please refer to the Elasticsearch setup page.