5.8.1

collectd: Fix BaseDir option. Thanks to Mariusz Białończyk and @rpv-tomsk. #2857
collectd: improve error handling, check return values. Thanks to @octo.
Build System: use kstat.h, when available. Thanks to Dagobert Michelsen and @rpv-tomsk. #2784
Build System: Fix distcheck on MacOS. Thanks to @rubenk.
Build System: add missing include of "collectd.h" to fix builds on Solaris. Thanks to @rpv-tomsk.
Build System: add endianess checks for AIX, fix GCC issue on Mac byteorder, fix byteorder on Solaris, add fallback for endianess conversion. Thanks to Dagobert Michelsen (multiple cherry picks from master).
Build System: Out-of-tree builds have been fixed. Thanks to @octo. #2602
Configuration: Error handling in the config parsing code has been improved. Thanks to @octo.
Documentation: Fix typo in collectd.conf(5). Thanks to @rpv-tomsk. #2760
Documentation: update note on dpdkstat. Thanks to @maryamtahhan. #2613
Various plugins: Errors found by the static code analysis tool Coverity were fixed. Thanks to @octo. #2559, #2560, #2561, #2562, #2563, #2565, #2568, #2575, #2579, #2580, #2588, #2589
Ceph plugin: A segfault has been fixed. Thanks to Aleksei Zakharov and Matthias Runge. #2572
DF plugin: fix memory leak in error case. Thanks to Takahashi tsc.
Exec plugin: check return value of plugin_thread_create(). Thanks to @octo.
Exec plugin: Handling of large groups has been fixed. Thanks to Sridhar Mallem. #2696
Exec plugin: Incorrect use of putenv(3) has been fixed. Thanks to Daniel Vrátil.
Exec plugin: A deadlock related to setting environment variables after fork() has been fixed. Thanks to Daniel Vrátil.
Intel PMU plugin: add core groups feature. Thanks to Kamil Wiatrowski. #2681
Intel PMU plugin: fix compatibility issue with collectd 5.8. Thanks to Kamil Wiatrowski.
Intel PMU plugin: fix possible NULL pointer dereference. Thanks to Kamil Wiatrowski. #2676
IPMI plugin: A segfault caused by a wrong data type has been fixed. Thanks to Mariusz Szafrański. #2742
IPMI plugin: The sensor configuration option has been fixed. Thanks to @rpv-tomsk. #2629
memcached plugin: A deadlock situation has been fixed. Thanks to @rpv-tomsk. #2612
NFS plugin: Support for NFSv4 has been fixed. Thanks to Jan-Philipp Litza. #2076
NTPd plugin: A memory leak in the error handling path has been fixed. Thanks to @rubenk. #2942
OVS Stats plugin: A deadlock situation has been fixed. Thanks to Volodymyr Mytnyk. #2590
OVS Stats plugin: Fix reconnect after thread terminated. Thanks to Volodymyr Mytnyk and @maryamtahhan. #2574
Perl plugin: A compilation failure has been fixed. Thanks to @rpv-tomsk. #2732
Perl plugin: Fix exporting notification meta data. Thanks to @octo.
RRDtool plugin: Handling of very large GAUGE metrics has been fixed. Thanks to Miroslav Lichvar. #2566
Tail plugin: Several regressions have been fixed. Thanks to @rpv-tomsk. #2535, #2587, #2611
turbostat plugin: A potential segfault due to an incorrect free() has been fixed. Thanks to @rubenk. #2948
UUID plugin: Fix hostname setting. Thanks to @rpv-tomsk. #2723
virt plugin: A segfault during error handling has been fixed. Thanks to @rubenk. {{Issue|2919]}
Write Kafka plugin: A build failure due to a deprecated API call has been fixed. Thanks to @rpv-tomsk. #2607, #2628, #2640
Write Prometheus plugin: Fix MHD_USE_INTERNAL_POLLING_THREAD flag in newer libmicrohttpd. Thanks to @rpv-tomsk. #2849
Write Prometheus plugin: set SO_REUSEADDRESS on listening socket. Thanks to @rpv-tomsk. #2570, #2673

5.8.0

collectd: The core daemon is now completely licensed under the MIT license.
collectd: Added daemon option to avoid making BaseDir. Thanks to Nathaniel Wesley Filardo and @octo. #2422
collectd: Global variables have been moved to their own module to make porting collectd easier. Thanks to Sean Campbell. #2467
collectd as well as Apache, memcached, OpenLDAP, Perl, RouterOS, SNMP, Tail-CSV plugins: Free userdata for plugin_register_complex_read(). Thanks to @rpv-tomsk. #2349
Collectd client library: Added parsing and server code. Thanks to @octo. #2258
Build system: Dependency on libltdl has been removed, support for libtool 1 has been dropped. Thanks to @rubenk. #1898
Build system: The build system has been switched to non-recursive make. Thanks to @rubenk. #2085
APC UPS plugin: The plugin's configuration is now optional. Without a <Plugin /> block reasonable defaults will be used. Thanks to @rpv-tomsk. #2351
Chrony plugin: Several issues found when working with a stratum-1 server have been fixed. Thanks to Miroslav Lichvar. #2190
Ceph plugin: Support for the Ceph version "Luminous" has been added. Thanks to Aleksei Zakharov. #2464
CPU plugin : Linux-specific "guest" states have been added. Thanks to Xavier G. #2439
cURL plugin, cURL-JSON, cURL-XML, DBI, FileCount, memcachec, Oracle, PostgreSQL, Table, Tail, Tail CSV plugins: The ability to configure the plugin field of generated metrics has been added. Thanks to @rpv-tomsk. #1944, #1681, #1558
cURL-JSON plugin: Parsing of arrays has been fixed. Thanks to @octo. #2281
DPDKEvents plugin: This new plugin reports link status and keep alive events. Thanks to Maryam Tahhan, Harry van Haaren, Serhiy Pshyk, Kim-Marie Jones, Krzysztof Matczak, Przemyslaw Szczerbik, Christian Ehrhardt and Luca Boccassi. #2157, #2348, #2400, #2405, #2417
DPDKStat plugin: The plugin has been refactored to make DPDK related utility functions reusable. Thanks to Krzysztof Matczak, Przemyslaw Szczerbik, Christian Ehrhardt and Luca Boccassi. #2130, #2348, #2400, #2405, #2417
DPDKStat plugin: The LogLevel and RteDriverLibPath config options have been added. Thanks to Jiri Prokes. #2505
Email plugin as well as Exec and Unixsock plugins: Use _SC_GETPW_R_SIZE_MAX. Thanks to @octo. #2451
FileCount plugin: Custom values for reported plugin, type and type instance. Thanks to @rpv-tomsk. #1979
GenericJMX plugin: Support for AtomicInteger and AtomicLong has been added. Thanks to Pierre Mauduit. #2158
gRPC plugin: Support for meta data has been added. Thanks to Taylor Cramer. #2378
IPC plugin: Fixed failed compilation on AIX. Thanks to @rpv-tomsk. #2357
Intel PMU plugin: This new plugin collects CPU performance metrics using Intel's Performance Monitoring Unit (PMU). Scaling information added to metadata. Thanks to Serhiy Pshyk and Roman Korynkevych. #2276, #2398, #2374
Intel RDT plugin: Support for collectd's logging infrastructure has been added. PQoS monitoring groups are being reset on start-up to fix potential previous unclean shutdowns. Thanks to Roman Korynkevych. #2089.
IPMI plugin: Support for System Event Log (SEL) has been added. Thanks to Roman Korynkevych. #2091
IPMI plugin: Support for remote IPMI controllers has been added. Thanks to @rpv-tomsk. #2024
LVM plugin: A check for the CAP_SYS_ADMIN capability has been added. This will give users an informative warning when the process is not running with the required privileges for this plugin. Thanks to @octo. #2426, #2499
mcelog plugin: This new plugin subscribes to Machine Check Exceptions (MCE) and dispatches notifications. Metadata reset. Thanks to Maryam Tahhan, Volodymyr Mytnyk, Taras Chornyi, Krzysztof Matczak and Roman Korynkevych. #2003, #2246, #2380
MQTT plugin: Add support for TLS in Subscriber blocks. Thanks to @octo. #2434
memcached plugin: Persistent connections have been implemented. Fix hit ratio reporting, add connections rate report. Thanks to @rpv-tomsk. #2388, #2385
memcached plugin: The type of the listen_disabled metric has been changed to total_events. Thanks to @octo. #2386, #2468
Netlink plugin: The dropped packets metric has been added. Thanks to Denys Fedoryshchenko. #2053
NFS plugin: Support for NFS 4.2 metrics has been added. Thanks to Marek Becka. #2369
NFS plugin: Config options to ignore specified NFS versions have been added. Thanks to Christian Bartolomäus. #2430
NUT plugin: The ConnectTimeout, ForceSSL, VerifyPeer and CAPath options have been added. Thanks to @rpv-tomsk and Steven Bell. #2145, #2354
OpenLDAP plugin: A segfault after a connection failure has been fixed. Thanks to @rpv-tomsk. #2377
Openvpn plugin: Added support for status files from latest OpenVPN-2.4 and possible from future versions. Thanks to @rpv-tomsk. #2352
OVS Events plugin: This new plugin reports link state changes from Open vSwitch (OVS). Thanks to Volodymyr Mytnyk. #1971
OVS Stats plugin: This new plugin reports bridge / interface statistics from Open vSwitch (OVS). Thanks to Volodymyr Mytnyk and Taras Chornyi. #2137
Perl plugin: Bugfix, added check of proper interpreter initialization. Thanks to @rpv-tomsk. #2391
PostgreSQL plugin: The plugin now sets the application_name parameter when connecting to the database. Thanks to daniacs. #2497
Processes plugin: The I/O operations reported for selected processes has been fixed. The metric ps_disk_octets has been renamed to io_octets because it actually contains the number of I/O operation by the process, not just disk related I/O. Same for io_ops (previously ps_disk_ops). The new metric disk_octets has been added and is reporting disk I/O only. Add option to collect the count of active memory maps for Linux processes. The CollectFileDescriptor and CollectContextSwitch options have been added. Thanks to @rpv-tomsk and to Wilfried Goesgens. #2232, #2454, #1989
Processes and TCPConns plugins: The OpenBSD implementation has been changed to use kvm_openfiles with KVM_NO_FILES. Thanks to Jeremie Courreges-Anglas. #2061
Python plugin: Extend Notification class to include metadata. Thanks to Volodymyr Mytnyk. #2135
Python plugin: The CollectdException class has been added. This allows to throw an exception without a stack trace being logged. Thanks to Sven Trenkel. #2330, #2346
Sensors plugin: Support for (electrical) current has been added. Thanks to Clemens Gruber. #2255
SNMP plugin: Error handling has been improved: a potential double-free is now avoided (potentially leaking memory) and handling of non-failing subtrees has been fixed. Thanks to @rpv-tomsk. ...

5.6.3

collectd: support for boolean string config values has been reintroduced. Thanks to @tokkee. #2083, #2098
collectd: The capability checking has been changed to use cap_get_proc(). Thanks to @mfournier. #2151
Documentation: A section documenting ignore lists has been added to collectd.conf(5). Thanks to @octo.
AMQP plugin: The ExchangeType option is now also valid for publishers. Thanks to @octo. #2286
Apache, Ascent, BIND, cURL, cURL-JSON, cURL-XML, nginx, Write HTTP plugins: Handling of URLs that redirect elsewhere has been fixed. Thanks to @rpv-tomsk. #2328
BIND plugin: Fix parsing of the sample time provided by BIND. Previously, the time was assumed to be in the local time zone when in fact it was in UTC. Thanks to Ed Ravin. #1268
BIND plugin: Memory leaks have been fixed. Thanks to @rubenk. #2303
Chrony plugin: Build flags have been fixed. Thanks to Thomas Jost and @mfournier. #2133
cURL-JSON plugin: The timeout value has been changed to default to the collection interval. This fixes a regression. Thanks to @mfournier.
cURL-JSON plugin: Handling of arrays has been fixed. Thanks to @octo. #2266
DBI plugin: Memory leaks at shutdown have been fixes. Thanks to @rpv-tomsk and @octo.
E-Mail, Exec, UnixSock plugins: Group ID lookup on systems with many groups has been fixed. Thanks to @rubenk and @octo. #2208
IPC plugin: A compilation error on AIX has been fixed. Thanks to @rpv-tomsk. #2305
LogFile plugin: If writing to the file fails, print log messages on STDERR instead. Thanks to @mfournier.
Log Logstash plugin: If writing the log entry fails, print it to STDERR instead. Thanks to @mfournier.
memcachec, Tail plugins: A resource leak in the matching infrastructure has been fixed. Thanks to Krzysztof Matczak. #2192
MQTT plugin: Invalid symbols in topic names are now replaced and a resource leak has been fixed. Thanks to Denys Fedoryshchenko. #2123
Network plugin: A potential endless-loop has been fixed. This can be triggered remotely by sending a signed network packet to a server which is not set up to check signatures. Thanks to Marcin Kozlowski and @rpv-tomsk. #2174, #2233, CVE-2017-7401
Network plugin: A use-after-free has been fixed. Thanks to @rpv-tomsk. #2375
Notify Email plugin: The plugin is no longer explicitly linked against libssl and libcrypto, relies on libesmtp being linked correctly. Thanks to @mfournier. Debian#852924
NTPd plugin: Calculation of loop offset and error has been fixed. Thanks to Neil Wilson. #2188
OpenLDAP plugin: An incorrect use of the ldap library, leading to a crash, has been fixed. Thanks to @mfournier. #2331
Perl plugin: A potential double-free has been fixed. Thanks to @octo. #2278
Perl plugin: Print an error when an incorrect configuration is encountered. Thanks to @rpv-tomsk. #927
RRDtool plugin: Incorrect handling of the flushes timeout option has been fixed. Handling of the RandomTimeout has been fixed. Thanks to @rpv-tomsk. #2363
SMART plugin: Some warning messages have been removed and the code has been cleaned up. Thanks to @octo. #2062
SMART plugin: A check for the CAP_SYS_RAWIO capability has been added. Thanks to @mfournier.
SNMP plugin: A double free has been fixed. Thanks to @rpv-tomsk. #2291
Write Graphite plugin: Error handling in the case that calculating a metric's rate fails has been improved. Previously, the raw counter values were sent to Graphite. Thanks to Iain Buclaw. #2209
Write Kafka plugin: A 32 bit random number is now used when formatting a random key. Thanks to @octo. #2074

5.7.2

Build system: The Notify Email plugin is no longer linked with indirect dependencies. Thanks to @mfournier.
collectd: A race condition when calculating a metric's rate has been fixed. Thanks to @octo. #1193
AMQP, Exec, UnixSock, Write Kafka plugins: Parsing of the PUTVAL command with multiple values has been fixed. Thanks to @octo. #2274
AMQP plugin: The ExchangeType option is now also valid for publishers. Thanks to @octo. #2286
BIND plugin: Fix parsing of the sample time provided by BIND. Previously, the time was assumed to be in the local timezone when in fact it was in UTC. Thanks to Ed Ravin. #1268
BIND plugin: Memory leaks have been fixed. Thanks to @rubenk. #2303
cURL-JSON plugin: Handling of arrays has been fixed. Thanks to @octo. #2266
DPDKStat plugin: Error handling during initialization has been improved. Thanks to @rubenk.
DPDKStat plugin: Handling of a number of metrics has been improved, for example rx_q0bytes. Thanks to Przemyslaw Szczerbik. #2167
Intel RDT plugin: Configuration handling has been changed to be more graceful. Thanks to Maryam Tahhan. #2165
Log Logstash plugin: If writing the log entry fails, print it to STDERR instead. Thanks to @mfournier.
LogFile plugin: If writing to the file fails, print log messages on STDERR instead. Thanks to @mfournier.
memcachec, Tail plugins: A resource leak in the matching infrastructure has been fixed. Thanks to Krzysztof Matczak. #2192
MQTT plugin: Invalid symbols in topic names are now replaced and a resource leak has been fixed. Thanks to Denys Fedoryshchenko. #2123
Network plugin: A potential endless-loop has been fixed. This can be triggered remotely by sending a signed network packet to a server which is not set up to check signatures. Thanks to Marcin Kozlowski and @rpv-tomsk. #2174, #2233, CVE-2017-7401
Perl plugin: A potential double-free has been fixed. Thanks to @octo. #2278
Processes plugin: A compilation error on AIX has been fixed. Thanks to @rpv-tomsk. #2210
SMART plugin: A check for the CAP_SYS_RAWIO capability has been added. Thanks to @mfournier.
Write Graphite plugin: Error handling in the case that calculating a metric's rate fails has been improved. Previously, the raw counter values were sent to Graphite. Thanks to Iain Buclaw. #2209
Write Prometheus plugin: An incorrect use of realloc(3) has been fixed. Thanks to @octo. #2275

5.7.1

collectd: Handling of boolean configuration options has been unified. Thanks to @tokkee. #2083, #2098
collectd: Reporting of internal statistics has been fixed. Thanks to @octo. #2108
collectd, various plugins: Bugs and issues reported by scan-build and coverity-scan have been fixed. Thanks to @rubenk and @octo.
Build system: Parallel build have been fixed. Thanks to @rubenk. #2110
DPDKStat plugin: Portability issues and a double-close bug have been fixed. Thanks to @rubenk and @mfournier.
[Intel RDT plugin](https://collectd.org/wiki/index.php/Plugin:Intel RDT): A check for the libpqos library version has been added. Thanks to Serhiy Pshyk.
NetApp plugin: Compilation problems have been corrected. Thanks to @octo. #2120
[Write Prometheus plugin](https://collectd.org/wiki/index.php/Plugin:Write Prometheus): A memory leak has been fixed. Thanks to @rubenk.

5.7.0

Documentation: The Turbostat plugin section has been improved. Thanks to @octo
Documentation: The semantics of the TypesDB option have been improved. Thanks to @octo.
collectd: A generic interface for parsing the text protocol has been added. Thanks to @tokkee. #1749
collectd: Threads now get named, making them easier to track using tools such as top, ps, etc. Thanks to Manuel Luis Sanmartín Rozada and @mfournier. #547
AMQP plugin, [Write Graphite plugin](https://collectd.org/wiki/index.php/Plugin:Write Graphite), [Write Kafka plugin](https://collectd.org/wiki/index.php/Plugin:Write Kafka): The new [Graphite]PreserveSeparator option allows retaining the default dot separator rather than escaping it. Thanks to @octo. #419
Battery plugin: A StateFS backend for gathering statistics has been added. Thanks to Rinigus. #1795
CPU plugin: CPU aggregation on AIX was fixed. Thanks to Chao Yang. #1957
Collectd::Unixsock: Fractional seconds support has been made more robust. Thanks to Matthias Bethke. #2052
DPDKStat plugin: This new plugin collects DPDK interface statistics. Thanks to Maryam Tahhan, Harry van Haaren, Taras Chornyi and Kim Jones. #1649
gRPC plugin: The DispatchValues option has been renamed to PutValues. Thanks to @octo.
HDDTemp plugin: The 32 devices limit has been removed. Thanks to Benjamin Gilbert. #631
Hugepages plugin: This new plugin reports the number of used and free hugepages on Linux. Thanks to Jaroslav Safka, Maryam Tahhan, Kim Jones and @octo. #1799
[Intel RDT plugin](https://collectd.org/wiki/index.php/Plugin:Intel RDT): This new plugin collects statistics exposed by Intel's Resource Director Technology . Thanks to SerhiyX. #1970
memcached plugin: The new Address option allows connecting to a different server than specified by the Host option. Thanks to Pavel Rochnyack. #1975
nginx plugin: Support for reporting failed connections has been added. Thanks to Pavel Rochnyack. #1609
Perl plugin: Significant internal reworking has been made. The new RegisterLegacyFlush option has been added. Thanks to Pavel Rochnyack. #1731
PostgreSQL plugin: Timestamps are now RFC 3339-formatted local time. Thanks to Igor Peshansky and Dave Cunningham. #1918
Processes plugin: Internal performance improvements have been made. Thanks to Pavel Rochnyack. #1980, #1981
RRDCacheD plugin: The plugin now tries to reconnect upon failed operations. Thanks to @tokkee. #1959
SpamAssassin: The plugin can now run in Perl's "tainted mode" (-T). Thanks to Akos Vandra. #1962
Tail plugin: Support for calculating latency distribution of matching values has been added. Thanks to Pavel Rochnyack and @octo. #1700
Tail plugin: The new GaugePersist option has been added. Thanks to @octo. #2015
Target:Set, Target:Replace, Match:RegEx: MetaData support has been added . Thanks to Igor Peshansky. #1922, #1923, #1930
turbostat plugin: The new LogicalCoreNames option allows switching to per-core naming rather than per-CPU. Thanks to Brock Johnson. #2056
virt plugin: The new BlockDeviceFormat and BlockDeviceFormatBasename options help controlling the names reported for block-device metrics. Thanks to Deyan Chepishev. #2004
[Write Graphite plugin](https://collectd.org/wiki/index.php/Plugin:Write Graphite): A new DropDuplicateFields option has been added. Thanks to Michael Leinartas. #1915
[Write Kafka plugin](https://collectd.org/wiki/index.php/Plugin:Write Kafka): The Key Random setting has been reintroduced. Thanks to @octo. #1977
[Write Log plugin](https://collectd.org/wiki/index.php/Plugin:Write Log): Support for formatting output in JSON has been added, using the new Format configuration option. Thanks to Igor Peshansky. #1924
[Write Prometheus plugin](https://collectd.org/wiki/index.php/Plugin:Write Prometheus): This new plugin publishes values using an embedded HTTP server, in a format compatible with Prometheus' collectd_exporter. Thanks to @octo. #1967

5.6.2

collectd: A compile error on AIX has been fixed: MSG_DONTWAIT is not available on AIX. Thanks to Chao Yang.
collectd: The capability checking has been rewritten to be more portable. Thanks to @octo. #2009
collectd.conf(5): Various typos have been fixed. Thanks to @mfournier.
collectd-tg: Incorrect usage of nanosleep() has been fixed which caused the tool to sleep (almost) indefinitely. Thanks to @octo.
Build system: Detection of the Java environment has been made deterministic to allow for reproducible builds. Thanks to @mfournier. #1523
Build system: Detection of the Lua headers has been improved. Thanks to @rubenk.
[APC UPS plugin](https://collectd.org/wiki/index.php/Plugin:APC UPS): Unavailable metrics are now skipped instead of reported as 0 (zero). Thanks to @octo. #2025
Modbus plugin: Build issues on FreeBSD have been fixed. Thanks to @octo.
OpenVPN plugin: Gracefully handle empty configurations. Thanks to Pavel Rochnyack. #1932
PowerDNS plugin: The "recursor command" has been fixed so PowerDNS can correctly parse all requested fields. Thanks to @rubenk.
[Write Graphite](https://collectd.org/wiki/index.php/Plugin:Write Graphite) and AMQP plugins: A bug that could lead to a missing null-termination has been fixed. Thanks to Markus Linnala.
[Write HTTP plugin](https://collectd.org/wiki/index.php/Plugin:Write HTTP): A logic error when checking the correctness of the data set has been fixed. Thanks to Pavel Rochnyack. #1996
[Write Kafka plugin](https://collectd.org/wiki/index.php/Plugin:Write Kafka): The Key Random config option has been fixed. Thanks to @octo. #1977
[Write Kafka plugin](https://collectd.org/wiki/index.php/Plugin:Write Kafka): Support for librdkafka 0.9.0 has been added. Thanks to @octo.
[Write Riemann plugin](https://collectd.org/wiki/index.php/Plugin:Write Riemann): Build issues on Solaris have been fixed. Thanks to @octo.
[ZFS ARC plugin](https://collectd.org/wiki/index.php/Plugin:ZFS ARC): A duplicate metric has been removed. Thanks to @rubenk. #1963

5.5.3

collectd: Write threads are stopped before shutdown callbacks are called. Thanks to @octo. #1110
collectd: A compile error on AIX has been fixed: MSG_DONTWAIT is not available on AIX. Thanks to Chao Yang.
libcollectdclient: Lines printed to STDERR are now guarded by the environment variable COLLECTD_TRACE. Thanks to @octo. #105
collectd.conf(5): Various typos have been fixed. Thanks to @mfournier.
Build system: Detection of the Java environment has been made deterministic to allow for reproducible builds. Thanks to @mfournier. #1523
[APC UPS plugin](https://collectd.org/wiki/index.php/Plugin:APC UPS): Unavailable metrics are now skipped instead of reported as 0 (zero). Thanks to @octo. #2025
Battery plugin: The minimum value has been removed from the power type to allow the plugin to report discharging batteries as negative power. Thanks to @octo.
DBI, Oracle and PostgreSQL plugins: An error message when the type instance is truncated has been added. Thanks to @octo. #4
cURL-JSON plugin: A possible segmentation fault when parsing unexpected JSON has been fixed. Thanks to @octo. #1896
DF plugin: Compilation with xfsprogs ≥ 4.7.0 has been fixed. Thanks to Thomas Deutschmann. #1877
Modbus plugin: Build issues on FreeBSD have been fixed. Thanks to @octo.
Network plugin: An error message has been corrected. Thanks to @octo.
Network plugin: Handling of errors form secure memory initialization has been improved: the plugin fails gracefully now instead of calling abort(). Thanks to @tokkee.
Network plugin: The gcrypt library is only initialized when it is actually required due to the network plugin's configuration. Thanks to @octo. #1902
Ping plugin: The init callback has been changed to be idempotent, fixing errors being reported on Solaris. Thanks to @octo. #869
PostgreSQL plugin: The query_plans and query_plans_by_table queries have been improved to return 0 (zero) instead of NULL when not available. Thanks to Bernd Zeimetz. #1905
PowerDNS plugin: The "recursor command" has been fixed so PowerDNS can correctly parse all requested fields. Thanks to @rubenk.
Python plugin: Handling of data sets with multiple data sources of different type has been fixed. Thanks to @tokkee.
RRDCacheD plugin: Reconnection behavior after failed operations has been added. Thanks to @tokkee. Debian#657877
[Write Graphite](https://collectd.org/wiki/index.php/Plugin:Write Graphite) and AMQP plugins: A bug that could lead to a missing null-termination has been fixed. Thanks to Markus Linnala.
[Write Kafka plugin](https://collectd.org/wiki/index.php/Plugin:Write Kafka): Support for librdkafka 0.9.0 has been added. Thanks to @octo.
[Write Riemann plugin](https://collectd.org/wiki/index.php/Plugin:Write Riemann): Build issues on Solaris have been fixed. Thanks to @octo.

5.6.1

Build system: Unnecessary linking of the [Write Graphite plugin](https://collectd.org/wiki/index.php/Plugin:Write Graphite) with libyajl has been removed. Thanks to @mfournier. Debian#839771, #1976
collectd: A bug in the FlushInterval option that caused a segmentation fault in the [Write HTTP plugin](https://collectd.org/wiki/index.php/Plugin:Write HTTP) has been fixed. Thanks to @octo. #1954
Apache plugin: A syntax error has been fixed. Thanks to @octo.
cURL-JSON plugin: A segmentation fault that occurred when handling JSON with unexpected structure has been fixed. Thanks to @octo. #1896
PostgreSQL plugin: Handling of NULL values in the query_plans and query_plans_by_table queries has been fixed. Thanks to Bernd Zeimetz. #1905
RRDCacheD plugin: Reconnection behavior has been added. Thanks to @tokkee. Debian#657877
VServer plugin: Use of a deprecated API (readdir_r()) has been fixed. Thanks to @tokkee.
[Write Graphite plugin](https://collectd.org/wiki/index.php/Plugin:Write Graphite): Make default values configurable at compile time again. Thanks to @octo. #1953
[Write HTTP plugin](https://collectd.org/wiki/index.php/Plugin:Write HTTP): A bug has been fixed that lead to flush callbacks being registered twice. Thanks to @octo. #1955

5.6.0

Build system: An option to to avoid building the DF plugin against XFS has been added. Thanks to @rubenk. #1878
Build system: Autoconf ≥ 2.60, a C99-capable compiler and pkg-config are now required. Thanks to @rubenk.
Build system: Building with -Werror is now optional. Thanks to @rubenk. #1222
Build system: Many compilation issues on non-Linux platforms have been fixed, leading to wider plugin support. Thanks to @rubenk, Dagobert Michelsen, Havard Eidnes and Robert Viduya.
Build system: The configuration summary now also ends up in config.log. Thanks to @tokkee.
collectd: All command-line options now override global options from the config file. Thanks to @tokkee. #366
collectd: A number of unit tests for commonly used functions have been added. Thanks to @octo.
collectd: Plugins start up and read timeouts are now logged. Thanks to @mfournier. #1293, #1254
collectd: Support for a timeout has been added to FLUSH callbacks. Thanks to Manuel Luis Sanmartín Rozada.
collectd: The -T command line switch now reports more errors. Thanks to Corey Kosak. #1642
collectd: The max size of value list elements (DATA_MAX_NAME_LEN) has been doubled and is now configurable at build time. Thanks to Amy Lin, @octo and Radu Brumariu. #1120
Set target: The MetaData option has been added. Thanks to Yves Mettier and Kevin Bowling. #1106, #1656, #1913
AMQP plugin, Write_HTTP plugin, Write_Kafka plugin: Support for libyajl < 2 has been added. Thanks to @octo.
[APC UPS plugin](https://collectd.org/wiki/index.php/Plugin:APC UPS): Parsing of end markers has been fixed. Thanks to @octo #617
[APC UPS plugin](https://collectd.org/wiki/index.php/Plugin:APC UPS): The PersistentConnection option has been added. Thanks to @octo #617
ceph plugin, DNS plugin, Exec plugin, IPTables plugin, Ping plugin, turbostat plugin: When running unprivileged, these plugins will now warn about insuffiscient permissions or capabilities(7). Thanks to @mfournier. #1530
Chrony plugin: This new plugin collects NTP data from the chrony NTP server. Thanks to Claudius Zingerli. #1548
cpusleep plugin: This new plugin measures time spent by CPU in deep sleep mode. Thanks to Rinigus. #1826
CPU plugin: The ReportNumCpu option has been added. Thanks to Fabien Wernli.
cURL plugin, cURL-JSON plugin, cURL-XML plugin: The new Statistics reports various per-HTTP connection timers. Thanks to @tokkee. #1004
DBI plugin: The Interval option has been added to Database blocks. Thanks to Michal Bebjak.
Disk plugin: Support for FreeBSD has been added. Thanks to Xin Li, Brad Davis, Ruben Kerfhof and Kevin Bowling.
[Empty Counter match](https://collectd.org/wiki/index.php/Match:Empty Counter): Support for derives has been implemented. Thanks to @octo. #1813
GenericJMX plugin: Support for TabularData and the PluginName option have been added. Thanks to David Crane. #1290, #1291
GPS plugin: This new plugin reports the number of sattelites seen by and precision of a GPS receiver. Thanks to Nicolas Jourden. #1346
gRPC plugin: This new client and server plugin allows sending and receiving metrics using the gRPC protocol. Comparable to the UnixSock plugin, but using TCP and TLS. Thanks to @tokkee and @octo.
Interface plugin: Reporting dropped packets has been added. Thanks to Marc Falzon. #1555
Interface plugin: The ReportInactive has been added, letting users skip inactive network interfaces. Thanks to Rinigus. #1791
Interface plugin: The new, Solaris-only UniqueName option has been added. Thanks to Yoga Ramalingam. #1416
Lua plugin: This new language binding allows writing plugins using the Lua programming language. Thanks to Julien Ammous, @octo and @rubenk.
Memory plugin: Reporting of ARC memory on Solaris has been added. Thanks to Brian ONeill.
MQTT plugin: This new plugin sends metrics to and/or receives metrics from an MQTT broker. Thanks to Marc Falzon, Jan-Piet Mens, Nicholas Humfrey and @octo. #805, #1124
MySQL plugin: Connection to the database server can now be done over SSL. Thanks to Brian Lalor. #1256
MySQL plugin: Monitoring slow queries has been added. Thanks to skob. #1773
MySQL plugin: mysql_bpool_pages-flushed has been renamed to mysql_bpool_counters-pages_flushed because the value is cumulative. Thanks to Marek Becka.
MySQL plugin: Support for Galera statistics has been added. Thanks to Rachid Zarouali. #1849
MySQL plugin: Support for InnoDB metrics was improved. Thanks to Aman Gupta. #1111
MySQL plugin: The mysql_sort type has been split into 3 different types. Thanks to Pavel Rochnyack. #1592
Network plugin: Decryption error logging has been improved. Thanks to Pavel Rochnyack. #1735
[Notify Nagios plugin](https://collectd.org/wiki/index.php/Plugin:Notify Nagios): This new plugin sends notifications to Nagios as a passive check result. Thanks to @octo.
NTPd plugin: The plugin now detects if the ntp daemon reports nanoseconds instead of microseconds. Thanks to Matwey V. Kornilov. #1783
OpenLDAP plugin: Several connection-related improvements have been made. Thanks to @mfournier. #1308
OpenLDAP plugin: Support for "simple authentication" has been added. Thanks to Marek Becka. #1087
Ping plugin: The Size option has been added, allowing the ICMP data payload size to be configured. Thanks to Witold Baryluk. #1395
PostgreSQL plugin, DBI plugin, Oracle plugin: The new PluginInstanceFrom option has been added. Thanks to Pavel Rochnyack. #1707
PowerDNS plugin: The recursor metrics have been updated to 3.7.3 and missing rr types have been added. Thanks to @rubenk.
Processes plugin: Counting of context switches was added for Linux. Thanks to Manuel Luis Sanmartín Rozada. #1036
Processes plugin: Improve reliability of thread counts on Linux. Thanks to Manuel Luis Sanmartín Rozada.
Python plugin: Minimal Python version requirement has been bumped to 2.6. ''Thanks to @rubenk. #1864
Redis plugin: Several additional metrics are now collected. Thanks to Marc Falzon and Matteo Contrini. #1807, #1483
Sensors plugin: The UseLabels option has been added. Thanks to Christian Fetzer.
SMART plugin: The new IgnoreSleepMode option has been added. Thanks to Scott Talbert. #1770
SMART plugin: The new UseSerial option allows identifying devices in a stable way. Thanks to Scott Talbert. #1794
SNMP plugin: The IpAddress can now be used for instances. Thanks to Vincent Bernat. #1397
StatsD plugin: Latency calculation histogram is now able to shrink automatically to optimal size. Thanks to Pavel Rochnyack. #1622
StatsD plugin: The CounterSum option has been added. Thanks to @octo. #929, #1282, #1311
UUID plugin: The plugin now also looks in in smbios system table and /sys/class/dmi. Thanks to @rubenk. #1490
virt plugin: The PluginInstanceFormat option has been added. Thanks to @rubenk. #1100
[Write Graphite plugin](https://collectd.org/wiki/index.php/Plugin:Write Graphite): The ReconnectInterval option has been added. Thanks to Toni Moreno and @octo.
[Write HTTP plug...