Release Notes for JMRI 5.15.2 release

Date: January 9, 2026

From: Bob Jacobsen

Subject: Test Release 5.15.2 of JMRI/DecoderPro is available for download.

Notes:

This is a test release. Please post a note if you encounter any new or old bugs! And please back up your JMRI files before installing this, in case you want to go back to an earlier version.

This is the next in a series of 5.15.* test releases. It requires at least Java 11 to work. We recommend that you use Java 21 if possible. (See our page on downloading Java) We expect this series to result in the next JMRI production release in July 2026. (See the tentative release schedule)

Some of the changes involved are quite extensive. They may require a certain amount of experience before they are working well. Therefore, this test release should be considered experimental. We would appreciate your feedback on it.

JMRI is now only available under the GNU General Public License. For more information, please see our copyright and licensing page.

Update From Older JMRI Versions

If you are currently using a version older than JMRI 5.0, please follow these instructions carefully:

1. Is your current version older than JMRI 4.12? If so, then update to JMRI 4.12 first, and ensure everything works correctly: check start-up, check things you need to be working, and check the JMRI log as well) before doing anything else. Store your configuration and panel files under a new name and use those from now on. Then continue with step 2.

   If you are currently using JMRI 4.7.3 or earlier on Linux or macOS (Windows doesn't need this), then it's very important that you update to JMRI 4.12 and carrying out the migration process described in the JMRI 4.12 release note before updating to any later release.

2. Is your current version older than JMRI 4.20? Then update to JMRI 4.20 first, and ensure that works correctly (check start-up, check things you need to be working, and check the JMRI log as well) before doing anything else. Save your preferences again. Store your configuration and panel files under a new name, use those from now on, and go on to step 3.
3. Is your current version older than JMRI 4.24? Then update to JMRI 4.24 first, and ensure that works correctly (check start-up, check things you need to be working, and check the JMRI log as well) before doing anything else. Save your preferences again. Store your configuration and panel files under a new name and use those from now on.
4. Is your current version older than JMRI 5.0? Then update to JMRI 5.0 first, and ensure that works correctly (check start-up, check things you need to be working, and check the JMRI log as well) before doing anything else. Save your preferences again. Store your configuration and panel files under a new name and use those from now on.
5. You can then install this release.

Following this multi-step order of updating via stable major releases safeguards you against possible migration issues that can arise from skipping these versions.

New problems with this release

• OperationsPro will crash when opening the Trains window if there are departure times in any of the train's routes.
• The "All Locos" roster group is not showing in the WiThrottle Server, hence not showing on the WiThrottle and Engine Driver apps.

If any of these effect you, please either wait for JMRI 5.15.3, due out in early February, rollback to JMRI 5.15.1 release which doesn't have the problem, or install a JMRI development build installer from Jenkins.

New warnings for this release:

• None Yet

Older warnings

See the JMRI 5.14 release note for more warnings predating the 5.15 development series, including pointers to various migration issues. These may be relevant to you if you're updating from an earlier version; we strongly recommend you update to at least JMRI 5.0 before installing this test release. See instructions above.

• Since JMRI 4.99.1 This test release, and all subsequent ones, require the use of Java 11 or later. We recommend that you use Java 21. Java 8 is explicitly not supported. There's more information on this migration on the JMRI Tech Road Map and JVM Capabilities pages.
• If you're using a Firefox web browser and opening JMRI help files locally (not over the web), a Firefox bug can sometimes cause it to enter a loop. There's a workaround in this JMRIusers post.
• Since JMRI 5.15.1 The serial communications library that JMRI uses has been updated. If your JMRI installation is having trouble communicating with your model railroad hardware, please contact us on the JMRI users group.

Download links:

These files are located in the JMRI 5.15.2 GitHub release.

Changes since Test Release 5.15.1:

The full list of included changes is available from our GitHub code repository.

Hardware Support

OpenLCB / LCC

• Fixed a problem adding signal masts when the OpenLCB or LCC system letter is not "M".

DecoderPro

• Some of the buttons have been relabelled for clarity
  • New Loco → New Entry
  • Identify → Find in Roster
  Along with machine translations for other languages.
• The window you use to assign roster entries to groups has been improved:
  • A "Create Group" button has been added to make that more convenient.
  • An edge-case where you could accidentally make a copy of the "All Entries" group has been removed.
  • A blank group name will no longer appear in the selection box.

LogixNG

• Fixes a bug where local variables might have the wrong values when using the action Execute delayed.

OperationsPro

• New feature, you can now build your train using "On Time" mode. Requires using real or fast clock to schedule for your trains.
• Locomotives can now use the quick service tracks feature.
• New tool to quickly enable tracks for quick service.
• Added pick up and set out times for locomotives.
• Trains now have a departure day.
• New automation acton item: Wait for automation to complete.
• New automation acton item: Down Counter.

Scripting

• Improve TransitActionsReport.py.
  • Sort the transit selection list by display names.
  • For sensors and signals in actions, use the display name instead of the system name.

Miscellaneous

• Added a 'JmriFaceless.command' to the macOS distribution that lets you run a faceless (no GUI) version of JMRI.
• Removed some code that was used for migration to JMRI 4.20 from earlier. If you're updating from before JMRI 4.20, please go through JMRI 4.20 as described in the migration instructions above.

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