Release note Software version 5.26.x

Applicable for e-Series and UR Series

For latest release notes of PolyScope X, please refer to Release note Software version 10.13.x

For further information please see the PolyScope 5 Software Handbook.

Download HERE

Date of release: July 10th 2026.

SW 5.26.0 Release Notes
Release Versions:

UR Software Update: 5.26.0
URSim Linux: 5.26.0
URSim Virtual Machine: 5.26.0
User Manuals: 5.26.0

Key Features

Support for CB5.6 Control Box
64-bit kernel update
Controller updated to 64-bit
PROFINET update
New Long Term Support (LTS) release
Changes to Primary/Secondary Interface
Improvement to servoj Lookahead

Important notes:

Software upgrade paths and compatibility flow

Control Box CB5.5	Control Box CB5.6
There are no change in upgrade path for users of Control Box CB5.5 and earlier models - Upgrade via URUP flow or by flashing a new image on an SD-card.	Users on CB5.6 must download and flash the SD-card using a special image marked “CB5.6” but otherwise following the same flow as always for flashing the SD-card.

Users participating in beta program

If you deployed a pre-release version of 5.26.0 on a CB5.5 or earlier, you must re-flash it to update to the release version of SW 5.26.0.

Motion+ URCap upgrade required

SW 5.26 and later contain architectural changes that break compatibility with the MotionPlus URCap version 1.5 and earlier versions. MotionPlus version 1.6 or higher is required.
Note that MotionPlus 1.6 is not compatible with SW 5.25 or earlier, so upgrading both components at the same time is required.

Long Term Support (LTS)

This version 5.26 will be a Long Term Support version, with support through to the end of 2027.

It includes support for:

UR e‑Series: UR3e, UR5e, UR7e, UR10e, UR12e, UR16e
UR Series: UR8 Long, UR15, UR18, UR20, UR30
Control Boxes CB5.0 through CB5.6
All model years of the above robots

Which updates will be provided during LTS support

During the support period for PolyScope 5.26 LTS, updates will focus on maintaining stability and ensuring continued compatibility for customers who depend on long term support. Updates will include:

Ensuring hardware and component compatibility for already supported robots, control boxes, teach pendants, and components. New hardware models introduced later will not be supported on this LTS version.
Safety compliance updates.
Critical bug fixes.

Please note that this is the major release of PolyScope 5.26 that is long term supported and which customers should qualify. Updates released to support new components, safety notices, or critical bug fixes will be delivered as minor patch releases listed as version 5.26.n, where n identifies the patch version.

64-bit kernel update

Kernel update:
This upgrade does not affect the behavior of existing programs and installations.
For enhanced hardware, driver and library compatibility we have performed a low-level Linux kernel update to add support for newer 3rd party hardware. Additionally the update changes the partition layout on the disk in order to switch to UEFI boot.

The Linux kernel was updated from 4.9 (32bit) to 6.6 (64bit) but user space remains 32bit only. In essence the update should be opaque for users of the system - that is URCaps and programs. If URCaps include modified device drivers, these must be recompiled.

PROFINET

This version introduces new PROFINET version certified against PROFINET specification 2.45.

New GSDML file: GSDML-V2.45-UR-PROFIsafe-20251201.xml

Backwards compatibility:

PLC programs made for previous software versions will run with no changes (Tested with Siemens 1500 and 1200 PLCs)
Internal configuration file for PROFINET is copied and migrated to the new PROFINET version.
New PLC programs should use the GSDML file released with this release.
Downgrade: All changes made after upgrade will be lost. Backup all data before upgrading.

Primary/secondary Interface

Added 4 bytes to the end of Configuration Data package. Additional bytes are only used by Universal Robots software and should be ignored.

RemoteTCP URCap Upgrade

The bundled Remote TCP URCap has been updated to support UR8LONG, UR15 and UR18 robots and adds support for the 64 bit OS kernel.

Servoj

Allow lookahead of down to 0.01s (instead of 0.03s) This enables shorter latency in external control applications, and allows servoj movements to settle faster to a target setpoint.

Documentation

Enhanced description of the RTDE protocol and data fields. Included possible values for enumeration fields such as robot mode and safety state.

Documentation is available at: https://docs.universal-robots.com/tutorials/communication-protocol-tutorials/rtde-guide.html

The field “target_gravity” has been added to the RTDE protocol. It contains data of the type “VECTOR3D” representing the currently active gravity input through the PolyScope mounting screen or using the “set_gravity()” URScript function
The field “target_base_acceleration” has been added to the RTDE protocol. It contains data of the type “VECTOR6D” representing the currently active external base acceleration input using the “set_base_acceleration()” URScript function with a postpended padding of three zeros

simulator_fault()

This function allows applications in URSim to simulate a safety system fault. This facilitates testing of error handling without a physical setup. The script function can be called either as a primary or secondary program while the robot is in ROBOT_MODE_RUNNING or as a secondary program when the robot is in ROBOT_MODE_POWER_OFF.

Return Value: None

simulator_fault_clear()

This function allows recovering from a simulated fault in URSim. The script function can only be called as a secondary program while the robot is in ROBOT_MODE_RUNNING or ROBOT_MODE_POWER_OFF.

Return Value: None

Bug Fixes

PolyScope GUI

Prevent automatic rename of duplicate variables in automatic and remote mode.
Fixed flight report generation filling up SD cards.
Fixed the bug were updating a feature from URCap API with unreachable pose was throwing exception.
Fixed controller connection issues occurring under high-load conditions.
Fixed issue where installation variable values could overwrite other variables when switching selection before confirming virtual keyboard input.
Fixed an issue were enabling SSH did not open port 22 in the firewall, preventing SSH/SCP connections.
Fixed IllegalArgumentException in Palletizing Nodes.
Fixed IllegalStateException when checking “Remember last item location” in pallet node.

Controller

Fixed issue with spare joints robot type mismatch. The robot type stored in the majority of joints will now be used.
Added drive power indicator to modbus runstate dependent choice.
Fix race condition that could lead to start / stop / pause / resume commands being ignored by the controller in extremely rare circumstances
Fixed an issue with abort commands in interpreter mode sometimes not aborting an ongoing move. This will work for both GroupInterrupt and GroupStop function blocks when using SRCI.
The URControl software has been compiled for a 64 bit kernel in contrast to the historical 32 bit kernel.
- It is known that there might be numerical differences between trigonometric math functions, e.g. cosine/sine functions between 32/64 bit architectures.
  Therefore, users of PolyScope 5.26+ may experience changed behavior in rare corner cases. For example, it is possible that a different inverse kinematic solution is found for poses, close to a singularity.
- The URScript primitives such as numbers, booleans, lists, structs etc. takes up a different amount of space on the heap and stack. The size of poses is unaffected, and the change to strings is marginal. The stack and heap space has been increased to mitigate the impact.
  If you hit the limit, a runtime error “The stack or heap overflowed.” will be triggered.
- URCap daemons may see a small runtime overhead when running on the 64-bit kernel. In most cases this is negligible; only very time-critical scenarios are likely to notice it.

Daemons can also be built and run as 64-bit. In that configuration they can perform better than a 32-bit daemon on a 32-bit kernel. However, because the runtime environment stays 32-bit for backwards compatibility, a 64-bit daemon must be statically linked and ship all required dependencies - it cannot rely on 64-bit system libraries.

Fixed issues where blends for displaying in PolyScope GUI were not sampled properly, causing them to not be shown in the GUI.
Fixed an issue causing controller to stop due to NaN values in safeAcos calculations in extremely rare circumstances when pausing a program.
Fixes issue where power demand during accelerations can cause 48V Voltage drop on UR20/UR30(C740A33). This change scales robot motion to a lower acceleration in cases where the voltage limit would have been exceeded.
Fixed C283A2 Safety System: Robot Moving when in Stop Mode, which could occur in some conditions during safeguard stop.
Fixed issue where force torque sensor calibration in very rare cases was not loaded when rebooting the robot arm, leading to incorrect force and torque readings.

Embedded

Features

Added brake-pin position monitoring, and updated brake algorithm to enhance brake engage reliability.

Bug fixes

Fixed Backdrive parking bug on UR series.
Fixed torque overload disagreement.
Fixed C338A0 PROFISafe: Critical error
Fixed C283A093 “Sanity check of target torque differs by X”
Fixed Cross monitoring disagreement issue between the Joint µA and µB MCU
- This update addresses scenarios reported when using UR‑series robots with size 2 joints (UR15, UR18 & UR8 Long), where demanding motion patterns control could lead to repeatable safety-related stops caused by current disagreement (C273A10 errors); with this release, customers can expect fewer unintended current disagreements for these robot types.

User Assistance

Manuals

Fixed incorrect description for ROBOT_MESSAGE_TYPE_KEY in https://docs.universal-robots.com/tutorials/communication-protocol-tutorials/primary-secondary-guide.html#key-message

Hardware Compatibility

This release introduces firmware support for the updated hardware variants of Joint Size 4f.

Robots produced before July 2026 must be updated with this software release when receiving new joints as the replacement parts. You must apply software update before installing the replacement parts.

Use the following table to find robot models corresponding to affected joint sizes:

Joint sizes	e-Series robots	HW compatibility updates
0	3e	not affected
1	3e, 5e, 7e	not affected
2	3e, 10e, 12e, 16e	not affected
3	5e, 7e, 10e, 12e, 16e	not affected
4	10e, 12e, 16e	not affected
	UR Series robots
Sz 2f	15	not affected
Sz 2.5f	20, 30	not affected
Sz 3f	15	not affected
Sz 4f	15, 20, 30	firmware update
Sz 5f	20, 30	not affected