Release of XLT 4.10


Release Overview

Xceptance has released version 4.10 of its load testing and test automation product, Xceptance LoadTest. This is a feature release. We strongly recommend to upgrade.

Here is a selection of the most important changes:

  • To make the migration to Java-based test cases easier, several APIs have been extended and driver and placeholder resolution was added to XLT.
  • A new Script Developer export template is available that creates more compact Java code.
  • The performance reports support the Apdex (Application Performance Index) now.
  • The requests metrics in performance reports can now be highlighted according to set criteria.
  • The XLT Jenkins plugin can be used in Jenkins Pipelines.

See below for more details. Make sure to read the full release notes:

Script Developer

As you may have heard already, Firefox 57 no longer supports XUL/XPCOM-based browser extensions (aka legacy extensions); these have been replaced with extensions built upon the WebExtension API. As a consequence, Script Developer cannot be installed and won’t work in Firefox 57 and above. Unfortunately, porting Script Developer to the WebExtension API cannot recreate the same user experience and functionality. Furthermore, user feedback told us that the possibilities of XML script test cases are often too limiting for today’s test automation needs. Therefore, Xceptance recently decided to discontinue the development of Script Developer. See our announcement for all the details.

But this does not mean that Script Developer is totally gone now. You can safely continue to use Script Developer with Firefox 52/ESR for another six months, or even beyond if you can use an outdated version of Firefox. We will continue to ship Script Developer as part of XLT and release maintenance updates if required.

So there is plenty of time for you to plan the migration of your script test suites. The designated migration path is to export your XML script test cases to Java test cases using the export functionality built into Script Developer.

Script developer runs on Firefox 45/ESR up to Firefox 56. We recommend using Firefox 52/ESR. Firefox 57 and higher is not supported.

Update Instructions: Firefox will not auto-update older versions of Script Developer to 4.10.0. You will need to do this manually. Please remove the currently installed version first and afterwards install the new version by simply dragging and dropping the file /tools/xlt-scriptdeveloper-4.10.0.xpi onto Firefox. Auto-updating within the 4.10.x product line will then work as usual again.

Alternatively you can visit the Mozilla Add-On marketplace and install Script Developer from there ( Please make sure you uninstall your locally installed version first.


Since the export of XML script test cases to Java-based script test cases is the designated migration path, we extended the Java scripting API and strengthened the support of Java-based test cases in general.

For instance, the framework can now create and handle the underlying WebDriver for you and will also take care of resolving placeholders in locator expressions and other parameters. The scripting API has been extended with new script commands (or better: methods) to make writing Java-based script test cases more comfortable. Now all script commands are also available as static versions that can be called from any class, giving you more freedom when designing your test suite.

Script Developer provides an alternative export template that makes use of all these new features and produces more compact Java code.

Load Test Report

The load test report comes with improvements as well. For each action, the report now lists the Application Performance Index (Apdex), a standardized metric to express user satisfaction when interacting with an application. Many values in the requests table can now be colored according to set criteria to quickly direct your attention to problematic areas.

You can now also choose whether you want events in your report listed grouped by test case or ungrouped, the latter giving you overall statistics. The report shows the maximum average CPU usage of an agent now, and agent charts can also be disabled if needed.

XLT Jenkins Plugin

Since Jenkins 2.x, build processes can be modeled as build pipelines. The XLT plugin for Jenkins can now be used in such a pipeline directly.