This page details the changes made in the current version only.
Earlier changes are detailed in the History of Previous Changes.

Version 5.5


New and Noteworthy

JMeter now supports Java 17

JMeter 5.5 ships with log4j2 2.17.2

Open Model Thread Group

New component: Open Model Thread Group allows creating load profiles with variable load.

For example, if you need to gradually increase load from 0/sec to 10/sec during minute you could previously use Thread Group + Timer combinations. However, then you need to compute the expected number of threads, ensure they are created only when needed, and so on.

With Open Model Thread Group you can configure the same load profile as rate(0/sec) random_arrivals(1 minute) rate(10/sec). The thread group would spawn threads as needed to drive the configured load. The load profile can use properties, so you can launch the same script with slightly different load levels, however, the profile can't be updated while the test is running.

The new thread group is experimental in JMeter 5.5, so please feel free to submit your feedback.

Open Model Thread Group sample
Open Model Thread Group sample

Preparing the deprecation of Oro Regex usage

Another experimental feature in JMeter 5.5 is the ability to replace the Oro based Regex implementation by the built-in Java based one. To choose the Java based one, set the JMeter property jmeter.regex.engine to the value java.

Core improvements

Kotlin language is now used in some core classes and tests (e.g. Open Model Thread Group). JMeter is compiled with apiTarget=1.5, and it ships with kotlin-stdlib 1.6.

lets-plot-kotlin charting library is added, so it will be easier to refine and create new charts in UI in the future.


Thread Groups

HTTP Samplers and Test Script Recorder

Other samplers



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

Report / Dashboard


Non-functional changes

Bug fixes

HTTP Samplers and Test Script Recorder

Other Samplers



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



Report / Dashboard




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

We also thank bug reporters who helped us improve JMeter.

Apologies if we have omitted anyone else.

Known problems and workarounds

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