---
title: "JMeter 5.6 Release Notes"
description: "Apache JMeter 5.6 release notes with 23 improvements and 15 bug fixes, plus upgrade notes from the official changelog."
url: https://docs.jmeter.ai/releases/5-6/
lastUpdated: 2026-10-01
source: docs.jmeter.ai
---

# JMeter 5.6 Release Notes

> **About these release notes**
> This page lists every documented change shipped in Apache JMeter 5.6, generated from the official changelog. For download and upgrade guidance, see [Download JMeter](/reference/download-jmeter/).

## Change summary

| Section | Changes |
| --- | --- |
| Improvements | 23 |
| Bug fixes | 15 |
| Non-functional changes | 43 |

## New and Noteworthy

## Improvements

#### Thread Groups

- [Issue#5682](https://github.com/apache/jmeter/issues/5682)[PR#717](https://github.com/apache/jmeter/pull/717) Open Model Thread Group: avoid skipping rows from CSV Data Set Config
- Support custom thread group implementations in “Add think time” and “Save as test fragment” actions
- Open Model Thread Group: interrupt pending HTTP requests and other `Interruptible` test elements on test stop

#### HTTP Samplers and Test Script Recorder

- [PR#5911](https://github.com/apache/jmeter/pull/5911) Use Caffeine for caching HTTP headers instead of commons-collections4 LRUMap
- [PR#5947](https://github.com/apache/jmeter/pull/5947) Fetch resources referenced in `<link "rel"="preload"...>` elements
- [PR#5869](https://github.com/apache/jmeter/pull/5869) Allow more templates to format sampler names in the recorder: `#{url}`, `#{method}`, `#{scheme}`, `#{host}`, `#{port}`

#### Other samplers

- [PR#5909](https://github.com/apache/jmeter/pull/5909) Use Caffeine for caching compiled scripts in JSR223 samplers instead of commons-collections4 LRUMap

#### General

- [PR#5792](https://github.com/apache/jmeter/pull/5792)Add KeyStroke for start_no_timers (Start no pauses: CRTL+SHIFT+n)
- [PR#5899](https://github.com/apache/jmeter/pull/5899)Speed up CPU-bound tests by skipping `recoverRunningVersion` for elements that are shared between threads (the ones that implement `NoThreadClone`)
- [PR#5914](https://github.com/apache/jmeter/pull/5914)Use `Locale.ROOT` instead of default locale for `toUpperCase`, and `toLowerCase` to avoid surprises with dotless I in `tr_TR` locale
- [PR#5885](https://github.com/apache/jmeter/pull/5885)Use Java’s `ServiceLoader` for loading plugins instead of classpath scanning. It enables faster startup
- [PR#5788](https://github.com/apache/jmeter/pull/5788)`FunctionProperty` no longer caches the value.     Previously it cached the values based on iteration number only which triggered wrong results on concurrent executions.     The previous behavior can be temporary restored with `function.cache.per.iteration` property.
- [PR#5920](https://github.com/apache/jmeter/pull/5920)Improve HTTP HeaderManager performance when it contains many headers: skip reinitialization on each iteration
- [PR#5920](https://github.com/apache/jmeter/pull/5920)Use AtomicInteger and AtomicLong instead of synchronized primitives for JMeterContextService#numberOfThreads
- [PR#5920](https://github.com/apache/jmeter/pull/5920)Cache bean properties in `TestBeanHelper` and avoid synchronization, so test plans with `TestBean`-based elements is faster
- [PR#5920](https://github.com/apache/jmeter/pull/5920)Improve computation when many threads actively produce samplers by using `LongAdder` and similar concurrency classes to avoid synchronization in `Calculator`
- [PR#5920](https://github.com/apache/jmeter/pull/5920)Reduce synchronization contention on `AbstractTestElement` that are shared between threads (the ones that implement `NoThreadClone`)
- [PR#5934](https://github.com/apache/jmeter/pull/5934)Added caching for date formatters for `__time` function
- [PR#710](https://github.com/apache/jmeter/pull/710)[Issue#5666](https://github.com/apache/jmeter/issues/5666)Added Shortcut key event for Reset search: `ctrl + alt + F`, `cmd + alt + F`
- [PR#5959](https://github.com/apache/jmeter/pull/5959)`TestElement` has been migrated to Kotlin, so nullable types are annotated better
- [PR#5944](https://github.com/apache/jmeter/pull/5944)Add PI for declaring `TestElement` schemas so element properties are easier to access in code (see `TestElementSchema`, `TestElement#getSchema()`, `TestElement#getProps()`)
- [PR#5944](https://github.com/apache/jmeter/pull/5944)Enable usage of `\${...}` expressions for checkbox controls (see context menus for checkboxes, however, the individual components should be adapted individually)
- [PR#678](https://github.com/apache/jmeter/pull/678)Experimental Kotlin and Java DSL for programmatic test plan generation (see [Creating a plan with Kotlin DSL](/usermanual/build-programmatic-test-plan/#treebuilder_kotlin_dsl))

## Bug fixes

#### HTTP Samplers and Test Script Recorder

- [PR#5901](https://github.com/apache/jmeter/pull/5901)Fix NumberFormatException when counter is empty or not a digit on Proxy Settings panel
- [PR#5987](https://github.com/apache/jmeter/pull/5987)[Issue#4546](https://github.com/apache/jmeter/issues/4546)Encode unicode characters in filenames when sending files in HTTP Sampler

#### Other Samplers

- [PR#5736](https://github.com/apache/jmeter/pull/5736)[Issue#5733](https://github.com/apache/jmeter/issues/5733)Allow `SampleResult#setEndTime` be set in `JSR223Sampler`

#### Listeners

- [Issue#5740](https://github.com/apache/jmeter/issues/5740)[PR#5741](https://github.com/apache/jmeter/pull/5741)Fix Aggregated Graph component to cope with empty names of samplers
- [Issue#5807](https://github.com/apache/jmeter/issues/5807)Fix an `ArrayIndexOutOfBoundsException` on HTTP parameters line on special case when key and value are empty,     i.e.: “`k1=v1&=&k2=v2`”
- [Issue#5654](https://github.com/apache/jmeter/issues/5654)[PR#5785](https://github.com/apache/jmeter/pull/5785) Fix `InfluxDBRawBackendListenerClient` missing data. Allow InfluxDB to insert multiple entries with the     same `timestamp` but with different `threadName`. Contributed by Victor Peralta (vperaltac at github)

#### Timers, Assertions, Config, Pre- & Post-Processors

- [PR#5717](https://github.com/apache/jmeter/pull/5717)Add jsonpath string to JSON Path Assertion error message so the error is easier to understand
- [PR#723](https://github.com/apache/jmeter/pull/723)Use correct number format on JSON Path Assertion. Contributed by andreaslind01 (andreaslind01 at gmail.com)

#### Report / Dashboard

- [Bug 66140](https://bz.apache.org/bugzilla/show_bug.cgi?id=66140)Guess the delimiter of the CSV source, when configured one seems wrong.     This is in line with the behaviour of CSVSaveService.

#### Documentation

- [Issue#5694](https://github.com/apache/jmeter/issues/5694)Document changed formatter for [__time()](/functions/time/). A warning will be logged,   if the code `u` is found in the format string, as the meaning for that code has changed from *day-of-week*   to *year*.

#### General

- [Bug 66157](https://bz.apache.org/bugzilla/show_bug.cgi?id=66157)[PR#719](https://github.com/apache/jmeter/pull/719)Correct theme for darklaf on rsyntaxtextarea
- [Issue#5872](https://github.com/apache/jmeter/issues/5872)[PR#5874](https://github.com/apache/jmeter/pull/5874)Trim name in Argument objects.
- [PR#693](https://github.com/apache/jmeter/pull/693)Avoid wrong results when `Object.hashCode()` happen to collide. Use `IdentityHashMap` instead of `HashMap` when key is `TestElement`
- Refresh UI when dragging JMeter window from one monitor to another, so rich syntax text areas are properly editable after window movement
- [PR#5984](https://github.com/apache/jmeter/pull/5984)`AbstractTestElement#clone` might produce non-identical clones if element constructor adds a non-default property value

## Non-functional changes

- [PR#725](https://github.com/apache/jmeter/pull/725)Add Chinese Simplified Translation for Open Model Thread Group
- [PR#5710](https://github.com/apache/jmeter/pull/5710)Add GitHub Issue templates
- [PR#5910](https://github.com/apache/jmeter/pull/5910)Use Caffeine for caching customizers in TestBeanGUI instead of commons-collections4 LRUMap
- [PR#5713](https://github.com/apache/jmeter/pull/5713)[PR#5931](https://github.com/apache/jmeter/pull/5931)Update Spock to 2.3-groovy-3.0 (from 2.1-groovy-3.0)
- [Issue#5718](https://github.com/apache/jmeter/issues/5718)Update Apache commons-text to 1.10.0 (from 1.9)
- [PR#5731](https://github.com/apache/jmeter/pull/5731)Update docs for `changeCase` function. `UPPER` is the default
- [PR#5924](https://github.com/apache/jmeter/pull/5924)Update Apache commons-io to 2.12.0 (from 2.11.0)
- [PR#5921](https://github.com/apache/jmeter/pull/5921)Update Jackson Core to 2.15.1 (from 2.13.3)
- [PR#5921](https://github.com/apache/jmeter/pull/5921)Update Jackson Databind to 2.15.1 (from 2.13.3)
- [PR#5725](https://github.com/apache/jmeter/pull/5725)Update Tika Parser to 1.28.5 (from 1.28.3)
- [PR#5725](https://github.com/apache/jmeter/pull/5725)Update JSoup to 1.16.1 (from 1.15.1)
- [PR#5725](https://github.com/apache/jmeter/pull/5725)Update Apache commons-net to 3.9.0 (from 3.8.0)
- [PR#5725](https://github.com/apache/jmeter/pull/5725)Update XStream to 1.4.20 (from 1.4.19)
- [PR#5763](https://github.com/apache/jmeter/pull/5763)[PR#5814](https://github.com/apache/jmeter/pull/5814)Updated Gradle to 8.1.1 (from 7.2)
- [PR#5854](https://github.com/apache/jmeter/pull/5854)Added Apache Httpclient5 5.1.3
- [PR#5833](https://github.com/apache/jmeter/pull/5833)Update Apache Freemarker to 2.3.32 (from 2.3.31)
- [PR#5830](https://github.com/apache/jmeter/pull/5830)Update Apache Groovy to 3.0.17 (from 3.0.11)
- [PR#5862](https://github.com/apache/jmeter/pull/5862)Update Apache Httpclient to 4.5.14 (from 4.5.13)
- [PR#5880](https://github.com/apache/jmeter/pull/5880)Update Apache Xalan to 2.7.3 (from 2.7.2)
- [PR#5854](https://github.com/apache/jmeter/pull/5854)Update Saxon-HE to 11.5 (from 11.5)
- [PR#5840](https://github.com/apache/jmeter/pull/5840)[PR#5930](https://github.com/apache/jmeter/pull/5930)Update accessors-smart to 2.4.11 (from 2.4.8)
- [PR#5837](https://github.com/apache/jmeter/pull/5837)Update asm to 9.5 (from 9.3)
- [PR#5840](https://github.com/apache/jmeter/pull/5840)[PR#5930](https://github.com/apache/jmeter/pull/5930)Update json-smart to 2.4.11 (from 2.4.8)
- [PR#5814](https://github.com/apache/jmeter/pull/5814)Update kotlin-stdlib to 1.8.21 (from 1.6.21)
- [PR#5889](https://github.com/apache/jmeter/pull/5889)[PR#5918](https://github.com/apache/jmeter/pull/5918)[PR#5814](https://github.com/apache/jmeter/pull/5814)Update kotlinx-coroutines-core to 1.8.21 (from 1.6.21)
- [PR#5889](https://github.com/apache/jmeter/pull/5889)[PR#5918](https://github.com/apache/jmeter/pull/5918)[PR#5814](https://github.com/apache/jmeter/pull/5814)Update kotlinx-coroutines-swing to 1.8.21 (from 1.6.21)
- [PR#5907](https://github.com/apache/jmeter/pull/5907)Update lets-plot-batik to 3.2.0 (from 2.1.1)
- [PR#5907](https://github.com/apache/jmeter/pull/5907)Update lets-plot-jvm to 4.3.0 (from 3.1.1)
- [PR#5859](https://github.com/apache/jmeter/pull/5859)Update log4j-1.2-api to 2.20.0 (from 2.17.2)
- [PR#5859](https://github.com/apache/jmeter/pull/5859)Update log4j-api to 2.20.0 (from 2.17.2)
- [PR#5859](https://github.com/apache/jmeter/pull/5859)Update log4j-core to 2.20.0 (from 2.17.2)
- [PR#5859](https://github.com/apache/jmeter/pull/5859)Update log4j-slf4j-impl to 2.20.0 (from 2.17.2)
- [PR#5861](https://github.com/apache/jmeter/pull/5861)Update neo4j-java-driver to 4.4.11 (from 4.4.6)
- [PR#5853](https://github.com/apache/jmeter/pull/5853)Update org.jetbrains:annotations to 24.0.1 (from 23.0.0)
- [PR#5868](https://github.com/apache/jmeter/pull/5868)[PR#5886](https://github.com/apache/jmeter/pull/5886)Update ph-commons to 10.2.4 (from 10.1.6)
- [PR#5861](https://github.com/apache/jmeter/pull/5861)Update reactive-streams to 1.0.4 (from 1.0.3)
- [PR#5847](https://github.com/apache/jmeter/pull/5847)Update rsyntaxtextarea to 3.3.3 (from 3.2.0)
- [PR#5839](https://github.com/apache/jmeter/pull/5839)Update svgSalamander to 1.1.4 (from 1.1.2.4)
- [PR#5852](https://github.com/apache/jmeter/pull/5852)Update xmlgraphics-commons to 2.8 (from 2.7)
- [PR#5854](https://github.com/apache/jmeter/pull/5854)Update xmlresolver to 4.6.4 (from 4.2.0)
- [PR#693](https://github.com/apache/jmeter/pull/693)Added randomized test GitHub Actions matrix for better coverage of locales and time zones
- [PR#5960](https://github.com/apache/jmeter/pull/5960)Add OpenJDK JMH for creating microbenchmarks in JMeter code
- [Issue#5961](https://github.com/apache/jmeter/issues/5961)Deprecate TestElement.threadName as it is not related to TestElement

## Thanks

We thank all contributors mentioned in bug and improvement sections above:

- Alex Schwartz, [@alexsch01](https://github.com/alexsch01)
- Andreas Lind, [@andreaslind01](https://github.com/andreaslind01)
- Arnout Engelen, [@raboof](https://github.com/raboof)
- Clay Johnson, [@clayburn](https://github.com/clayburn)
- David Getzlaff, [@dgetzlaf](https://github.com/dgetzlaf)
- Kai Lehmann, [@lehmannk](https://github.com/lehmannk)
- kaola89, [@kaola89](https://github.com/kaola89)
- Matt Tansley, [@matthewt-assurity](https://github.com/matthewt-assurity)
- Mohamed Ibrahim, [@rollno748](https://github.com/rollno748)
- Ori Marko, [@orimarko](https://github.com/orimarko)
- PJ Fanning, [@pjfanning](https://github.com/pjfanning)
- Sandra Thieme, [@sandra-thieme](https://github.com/sandra-thieme)
- Stefan Seide, [@sseide](https://github.com/sseide)
- Victor Peralta, [@vperaltac](https://github.com/vperaltac)
- Vincent DABURON, [@vdaburon](https://github.com/vdaburon)

We also thank bug reporters who helped us improve JMeter.

Apologies if we have omitted anyone else.

## Useful links

- [Download JMeter](/reference/download-jmeter/)
- [Getting started guide](/getting-started/get-started/)
- [All release notes](/releases/)
- [Current changes page](/user-manual/changes/)
- [History of previous changes](/user-manual/changes-history/)