The new agent.variant item returns the variant of Zabbix agent - '1' for Zabbix agent and '2' for Zabbix agent 2.
The new vmware.hv.maintenance item returns '0' when the hypervisor is not in maintenance and '1' when the hypervisor is in maintenance.
The new vmware.hv.sensors.get item returns a JSON with various VMware hardware system health data.
The docker.container_stats  item now also returns CPU usage in percentage as part of container resource usage statistics.
The system.hostname item can now return only shorthost (part of the hostname before the first dot) and, optionally, transform the hostname into lowercase. See Zabbix agent items for details.
The new optional parameter persistent_dir specifies a directory for storing a file with a state of log, log.count, logrt or logrt.count item.
The state includes the log file name, size, position how far the log file was analyzed, MD5 sums for identification of file and a few more attributes.
Its purpose is restoring of more detailed state of the log* item in Zabbix agent memory when the agent is started than available from Zabbix server.
It was developed for using in Unix environments with mirrored disks or filesystems supporting snapshots where Zabbix agent can be stopped and later started from a split-off disk copy or a filesystem snapshot.
If Zabbix agent is often stopped/started the new parameter can be also useful on simple filesystems for better protection against analyzing the same records twice or skipping records.
Read the persistent files notes for more information before using it.
The ability to handle compressed content has been added to Zabbix web monitoring. All encoding formats supported by libcurl are supported.