Release Notes for Zabbix 1.8.21

Zabbix Team is pleased to announce the availability of Zabbix 1.8.21.

Zabbix is an enterprise-class open source distributed monitoring solution. Zabbix is released under the GPL, thus it is free of charge for both commercial and non-commercial use. A complete text of the license is available at

This document contains the release notes for Zabbix 1.8.21. Download here.

The following sections describe the release in details and provide late-breaking or other information that supplements its main documentation.

Fixes and minor improvements

ZBX-3407 fixed NVPS query to not fail on DB2 Frontend
ZBX-8608 added support of IP masks for action conditions Frontend Proxy Server
ZBX-8151 fixed XXE vulnerability on XML import using obsolete libxml versions; thanks to pnig0s@Freebuf for the report API Frontend
ZBX-8343 fixed a bug in binary heap that could cause a slightly inconsistent ordering of elements in the queue Agent Proxy Server
ZBX-8198 decreased verbosity of Windows agent with DebugLevel=4 Agent
ZBX-7930 improved SQL performance and execution time in Maintenance page API Frontend

Installation and Upgrade Notes


See Zabbix documentation for full details.


See Upgrade procedure for upgrade options and instructions. For version specific upgrade notes, see Upgrade notes for 1.8.21.

Commercial support

Zabbix Company provides a full range of Professional Services. We also provide trouble-free Upgrade Service for easy migration from earlier versions of Zabbix. Please Contact sales for pricing and more details.


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