Release Notes for JMRI 5.15.3 release
Date: January 21, 2026
From: Release Pumpkin
Subject: Test Release 5.15.3 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)
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:
- 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.
- 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.
- 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.
- 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.
- 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
New warnings for this release:
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 5.15.3 GitHub release.
The
full list of included changes is available from our
GitHub code repository.
Hardware Support
- Fixed a problem adding signal masts when the
OpenLCB or LCC system letter is not "M".
- Improved display of stream data frames in the Monitor.
- Improved how traffic from an internal hub is
displayed in the Monitor.
- Updated the OpenLCB library to properly display
Stream-related messages.
- The JmriFaceless application can now open an OpenLCB/LCC Hub
OperationsPro
- Added new dialog message to the Trains window confirming termination of built trains.
- Fix a bug that would crash the Train and Route windows if there were departure times in the train's route.
- Improvements to staging tracks when using the new on time mode.
- Added a "Reset All Trains" button to the Trains window.
WiThrottle Server
- Fixed a problem introduced in JMRI 5.15.2 where the
"All Entries" roster group would not appear in WiThrotte
and Engine Driver.
Miscellaneous
- Testing - The JUnit4 RetryRule class has been removed as implementing
tests have been updated to JUnit5