net.dnsZabbix agent item does not support IPv6 addresses in its first parameter.
IPMI checks will not work with the standard OpenIPMI library package on Debian prior to 9 (stretch) and Ubuntu prior to 16.04 (xenial). To fix that, recompile OpenIPMI library with OpenSSL enabled as discussed in ZBX-6139.
Some Linux distributions like Debian, Ubuntu do not support encrypted private keys (with passphrase) if the libssh2 library is installed from packages. Please see ZBX-4850 for more details.
Zabbix server or proxy that uses MySQL as its database may or may not work correctly with MySQL ODBC library due to an upstream bug. Please see ZBX-7665 for more information and available workarounds.
There is a bug in fping versions earlier than v3.10 that mishandles duplicate echo replay packets. This may cause unexpected results for
icmppingsec items. It is recommended to use the latest version of fping. Please see ZBX-11726 for more details.
If the OpenBSD operating system is used, a use-after-free bug in the Net-SNMP library up to the 5.7.3 version can cause a crash of Zabbix server if the SourceIP parameter is set in the Zabbix server configuration file. As a workaround, please do not set the SourceIP parameter. The same problem applies also for Linux, but it does not cause Zabbix server to stop working. A local patch for the net-snmp package on OpenBSD was applied and will be released with OpenBSD 6.3.
It has been observed that frontend locales may flip without apparent logic. A known workaround to this is to disable multithreading in PHP and Apache. Please see ZBX-10911 for more information.
Zabbix server may generate slow select queries in case of non-existing values for items. This is caused by a known issue in MySQL 5.6/5.7 versions. A workaround to this is disabling the index_condition_pushdown optimizer in MySQL. For an extended discussion, see ZBX-10652.
Several operations can be assigned to the same step. If these operations have different step duration defined, the shortest one is taken into account and applied to the step. But due to bug there was exception to this rule when step duration is set to 0, it would use default value instead of shortest one. Now there will be no exception and default step duration will only be used if it's shortest, this is equivalent to behavior that frontend shows and user expects. Affects all versions, fixed in 2.2.17rc1, (see ZBX-11534 for more information).
A large number of open user sessions can be created when using custom scripts with the
user.login method without a following
Due to a net-snmp bug, IPv6 address may not be correctly displayed when using SNMPv3 in SNMP traps. For more details and a possible workaround, see ZBX-14541.
logrtitems repeatedly reread log file from the beginning if file system is 100% full and the log file is being appended (see ZBX-10884 for more information).