Release Notes for JMRI 5.17.4 release

Date: Oct 10, 2026

From: Bob Jacobsen

Subject: Test Release 5.17.4 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 5.17.* 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 December 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

• None yet

New warnings for this release:

• This version has an updated Windows launcher, which might cause Windows to emit some security warnings until it's been used enough times that Windows calms down.
• Memory Input Icons, Global Variable Input Icons and Block Contents Input Icons in Layout Editor, Panel Editor and Control Panel Editor have for a long time shown a shadow border by default instead of no border by default. This made it impossible to display them without a border, unlike other editor icons. This has been fixed. If you want a border on one of these icons and no longer see one, use the contextual menu on the icon to set the border width to a non-zero value.

Older warnings

See the JMRI 5.16 release note for more warnings predating the 5.17 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 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.

Download links:

These files are located in the JMRI 5.17.4 GitHub release.

Changes since Test Release 5.17.3:

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

Hardware Support

DCC++ and DCC-EX

• Correct E-Stop command sent when throttle is in reverse.

Lenz XPressNet

• A throttle waiting for a reply which never arrives now gives up and resumes sending: after 5 seconds once the connection has nothing left in hand, 15 seconds otherwise. On a serial XpressNet connection a broadcast message arriving while a command is in flight could be taken for that command's reply, leaving the throttle waiting forever and silently holding back every command queued afterwards for the rest of the session.
• Roco and Z21 throttles now stop their timers when they are disposed of, instead of leaving them running for the rest of the session.

LocoNet

• Fixed a problem where an Intellibox-II would have power on/off problems after CV programming.
• A LocoNet connection now reconnects if the connection goes down and then comes up again.
• Add summary panel to SlotMon, and fix up the Layout Reset and Show Idle.

OpenLCB / LCC

• The "Make Sensor" and "Make Turnout" buttons in the configuration panel used to require a non-empty description field to put a user name on the Sensor/Turnout they'd create. Absent that, they wouldn't appear. A description is no longer required; if one is not present, the Sensor or Turnout will be created without a user name.
• Updated OpenLCB / LCC Reporters to set the RailCom orientation instead of direction (WEST/EAST if the appropriate bit is set in the report).
• Updated OpenLCB / LCC Reporters to query current occupancy and present locomotives from layout hardware upon creation and startup, correctly populating the initial report and collection.
• Updated the OpenLCB jar library to pick up a fix to the read/write timeout value calculation.

New / Updated decoder definitions

Public Domain and DIY decoders

• Added EL-HO decoder for cars Rybák

Control Panel Editor

• Memory Input Icons, Global Variable Input Icons and Block Contents Input Icons have for a long time shown a shadow border by default instead of no border by default. This made it impossible to display them without a border, unlike other editor icons. This has been fixed. If you want a border on one of these icons and no longer see one, use the contextual menu on the icon to set the border width to a non-zero value.
• Memory Input Icons, Global Variable Input Icons and Block Contents Input Icons now work properly when the panel has been zoomed larger or smaller.

CTC Tool

• Updated the "newer" CTC Tool's web page to show that the "CTCParts" web site is functioning.

DecoderPro

• DecoderPro's locomotive files now track the last-seen state of variable values. This has no effect right now, but may be useful information in the future.
• The way that DecoderPro tracks the state of CVs and variables has been updated to be more comprehensive. This should have no impact on users now, but allows us to store a more accurate state (see item above).
• Fixed an exception when you closed the Labels&Media pane without saving first.

Dispatcher

• Fixed a bug where auto trains could not be run after the Dispatcher window had been closed and reopened in the same JMRI session.

Dispatcher System

Internationalization

• Czech language improvements.

Layout Editor

• Memory Input Icons, Global Variable Input Icons and Block Contents Input Icons have for a long time shown a shadow border by default instead of no border by default. This made it impossible to display them without a border, unlike other editor icons. This has been fixed. If you want a border on one of these icons and no longer see one, use the contextual menu on the icon to set the border width to a non-zero value.
• The popup menu for Memory Input Icons now lets you set the number of columns that the GUI will display. Note that the fixed width interacts with selection: If you select a wider fixed width, blank areas will display on either side.
• A bug introduced in JMRI 5.17.3 would cause display problems with layout editor windows that had been zoomed. This has been fixed.
• Memory Input Icons, Global Variable Input Icons and Block Contents Input Icons now work properly when the panel has been zoomed larger or smaller.
• Add the input option for LogixNG global variables.
• Improve the selection process for choosing label icons or input icons for memory variables, block contents and LogixNG global variables.
• The background colors on LE panels and their web versions did not always match. For example, a "light gray" background was substantially lighter on the web. This is now fixed for background and track-drawing colors. Some icon backgrounds and borders can still have mismatches.

LogixNG

• Fix issues relating to the ActionPositionable and ActionPositionableByClass actions.

Panel Editor

• Memory Input Icons, Global Variable Input Icons and Block Contents Input Icons have for a long time shown a shadow border by default instead of no border by default. This made it impossible to display them without a border, unlike other editor icons. This has been fixed. If you want a border on one of these icons and no longer see one, use the contextual menu on the icon to set the border width to a non-zero value.
• Add the input icon option for the blocks

Turnouts, Lights, Sensors and other elements

• In the Reporters table, the Report column now displays all reported objects concatenated with " + " when the reporter is a CollectingReporter.

Web Server

• Some improvements to how the various input icons are handled on panels:
  • The padding on the end of the icon now agrees with what's on the parent JMRI panel.
  • The default drop shadow on the web has been dropped to make the appearance agree with the parent JMRI panel.
  • The default border now agrees with the border on the parent JMRI panel.
• If an icon is defined in JMRI as having no background, it's shown as transparent on the JMRI screen. Previously, this was shown as a white background on the web browser screen. This has been corrected so that it now shows on the web browser screen as transparent, giving the same appearance as on the JMRI screen.

Miscellaneous

• The "noverify" option has been removed from the JMRI program launchers so that JMRI can use Java 27 and later.
• For JMRI developers: CI tests now fails on WARN logging messages.

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