PRTG Release Notes:
Preview Channel

Various other minor fixes and improvements, updated user manual.

We updated the German and Spanish language files.

We updated the German and Spanish language files for certain sensor types.

We fixed an issue for the VMware Datastore (SOAP) sensor that created an extra non-functioning channel when you have set your PRTG to a different language than English, for example German or Spanish. This channel did not deliver any values and therefore generated an error status, while the actual Free Space channel continued to function. Please note that existing VMware Datastore (SOAP) sensors will still show this extra channel when you update to this PRTG version, the fix applies when you create this sensor type new.

We fixed an issue for the Windows Updates Status (PowerShell) sensor which has been reporting the following error since the last Windows update from October 14th, 2025: Update history does not contain any entries. Please enable the sensor debug options and contact support for further help. The issue happened when your target system was Windows Server 2025 or Windows 11 updated to latest Windows patches.

To update to this Preview 25.x.114 and subsequent PRTG versions, you must first install the following PRTG version: 25.4.112.1179 Preview. PRTG 25.4.112.1179 serves as an intermediate version when you want to update from older PRTG versions to this and subsequent versions. This step is necessary because we had to migrate our codesigning certificates to a new Cloud endpoint.

You can verify the authenticity of the PRTG installer with the Secure Hash Algorithms for the following versions and release channels:

Preview 25.4.114.1009

• sha256_exe 3432ECFC34110840592910BA4ABEA2370C99F154EFD2D9DEF7D6AB22F48D8E39
• sha256_zip 3A2FEC24B66BF24B2FB6B7CB1C8D6381FB9C653CB4F04E9452927B82D24476B7

Preview 25.4.114.1040

• sha256_exe 825D6A03B097844ACBEB529CE27B7CBA07B7A97606AF42A6553B138E867695C9
• sha256_zip 37E33BDC271218FFD135479395B8DD14FF1D629583D96FBEE307DD1BE758B810

• You are now able to create the following sensor types with the new endpoint /experimental/devices/{id}/sensor via POST request: EXE/Script sensor. The new endpoint is listed under the Sensors section in Swagger UI and gives you information about supported sensors.
• The schemas endpoint /api/v2/schemas now returns the lookupkey value correctly, for example lookupkey = intervalid or usergroupid.
• We removed the field kind_variant from all endpoints. This field returned, for example, the value device when you executed a GET request on the api/v2/devices endpoint.
• We changed the Schemas endpoint experimental/schemas/{kind} in PRTG API v2 so that it is replaced with the following endpoints: experimental/schemas/{parent}/post (for creating objects), experimental/schemas/{id}/patch (for updating objects) and experimental/schemas/{id}/get (for reading objects). You can use the include parameter as a filter for these endpoints in your requests.
• The Web.log will now create log entries when you execute an API request in PRTG API v2 Swagger UI with an invalid or deleted API key. Requests via API v2 with invalid API keys were not logged before.

We fixed an issue for the logout button which was not displayed within the mobile view window and where you had to scroll down to the end of the page in order to logout.

We updated the German and Spanish language files.

We fixed an issue that occurred on PRTG stable version 25.3.110.1313 for Paessler PRTG Hosted Monitor where invited users were not able to log in to the respective instance. The error message displayed was You are not authorized to access this PRTG instance.

You can verify the authenticity of the PRTG installer with the Secure Hash Algorithms for the following versions and release channels:

Preview 25.4.112.1179

• sha256_exe B2D56B357EDCBBC30AA205ADE2E2C827E10FD061CD3FD9B97CAB02379404050E
• sha256_zip FBA805B27BFC26F8793B9A1D17AFE1BDE2349373FE300971AC8878438EBD334D

We further hardened PRTG by improving input sanitization.

Various other minor fixes and improvements, updated user manual.

We fixed an issue for the REST Custom v2 sensor where the JSONPath setting for session based authentication was not correctly processed when you selected JSON format as Login Result Type. The login would fail with a 200 HTTP response code, instead 201 (created) should have been returned.

You can verify the authenticity of the PRTG installer with the Secure Hash Algorithms for the following versions and release channels:

Preview 25.3.112.1160

• sha256_exe 316F088E294DC02ED562FF7B5FFD154F17DC3ECAE6C009CED1D369349C0B2E06
• sha256_zip 62D3DA7FE43FA5E2F44EC21BB3EEE66D23EBB00CA5772FEED6815884063EC413

• We improved the experimental endpoint /experimental/devices/{id}/sensor to accept certain sensor types via POST request when those sensor types have a version number in their name. The endpoint will now accept those sensor types with or without the version number. This change affects the AWS Cost sensor and Ping v2 sensor for now. You will also find an additional note under this endpoint listing the supported sensors.
• We improved the handling for endpoints in PRTG API v2 that are not available for Paessler PRTG Hosted Monitor instances. For the endpoint /users/reset-password, for example, we now display a note that the endpoint is not available on Paessler PRTG Hosted Monitor. When you execute a POST request on this endpoint for password reset, you will receive a HTTP 501 error repsonse that this method was not implemented yet.

We fixed an issue that occurred when you logged out of the new UI on mobile view. Upon logout, an unknown error would be displayed.

We fixed an issue on the sensor overview page that occurred sporadically. The issue could happen when you navigated to the sensor overview page and would show an error popup window on the channel gauge view.

With this PRTG version we introduce the new SNMP Linux Disk Free v2 sensor which is the successor to the SNMP Linux Disk Free sensor. This sensor monitors the free space on disks of a Linux/Unix system via SNMP. The SNMP Linux Disk Free v2 sensor is also compatible with the Multi-Platform Probe.

We updated our HTTP Client Axios for Browser and node.js to version 1.11.0 which fixes a critical vulnerability regarding the used form-data version.

We hardened PRTG by improving input sanitization.

We updated the sensor schema for certain sensor types that is used for setting channel limits. Affected sensor types are the Script v2, SSH Script v2 (BETA) and REST JSON Data sensor (BETA) sensor. The schema was updated to version 3, which ensures support for setting channel limits.

Various other minor fixes and improvements, updated user manual.

The Activation Token that shows the identifier of your license is now also displayed for PRTG offline license activations. You will see the Activation Token below your System ID on the License Status page when you select Manual (offline activation) for your license.

We fixed an issue that could occur during PRTG getting online activation data for a license and if PRTG encounters an exception at the same time. For example, in case of an 500 server error, PRTG would stop completely during activation resulting in an unavailable web interface. PRTG will now catch the exception and list it in the CoreActivation.Log. Furthermore, the PRTG web interface will be available and will direct you to the landing page /activation.htm in these cases.

We fixed an issue regarding Overload Protection, where PRTG would display the message Warning! Overload protection is active! Click here to learn more even in cases when no Overload Protection was active due to how the value addition is handled for failed login attempts. For more information about Overload Protection and why it is used in PRTG, please see our Knowledge Base article: What is overload protection?

You can verify the authenticity of the PRTG installer with the Secure Hash Algorithms for the following versions and release channels:

Preview 25.3.111.1263

• sha256_exe 1047ED7222A9E9D89C4F9308A6EE2A1FFDFD02120886765DE3CA7D8DE6E7C2B1
• sha256_zip 45678F81E731DC482ACA2F1783542215922A08540B321488CF41179C951D1D8C

• We fixed an issue where it was possible to move the ProbeDevice via endpoint /experimental/devices/{id}/move to another Group/Device/Probe. The issue occurred also for the actions clone and delete via APIv2. The ProbeDevice is fixed in PRTG and cannot be deleted, cloned or moved anymore via APIv2.
• The IP address is now logged in the core logfiles, furthermore the Audit Log, in case of a failed login via ApiToken-Provider. The issue occurred in the PRTG application server where the IP address was not set in previous PRTG versions and thus could not be logged in those cases.
• You are now able to create the following sensor types with the new endpoint /experimental/devices/{id}/sensor via POST request: AWS Cost sensor, Cloud Ping sensor. The new endpoint is listed under the Sensors section in Swagger UI and gives you information about supported sensors. All setting sections, including lookups, are supported for this sensor type.
• We have added the field primary that is included in the response code when you execute a GET request on the endpoint /experimental/channels. When you filter for the primary field (true or false) you will receive a list of primary or non-primary channels accordingly.
• We fixed an issue for the experimental endpoint /experimental/devices that returned the status PAUSED_UNTIL for paused objects by user when you executed a GET request. This status did not match our Schema and will now return PAUSED_BY_USER_UNTIL for objects that were paused by user until a certain date or time.
• We added two experimental endpoints /experimental/usergroups/{id} and /experimental/usergroups to PRTG API v2 that return a list of created user groups or by ID when you set the include parameter first upon a GET request.

• We fixed an issue for the PRTG application server that ignored parsing errors of the appserver.config.yaml and started with a default configuration. The PRTG application server will no longer start in this case and exit immediately, leaving a panic logfile with a message that explains the issue. This happened, for example, if lines for accesskey and clientuuid existed in the appserver.config.yaml.
• We fixed an issue for the PRTG application server that occurred when you updated to PRTG version 25.2.108.1358. The PRTG application server would crash sporadically in certain cases and create a panic logfile with the message: panic: runtime error: invalid memory address or nil pointer dereference.

We added the option to select a sensor as dependency in the settings Schedules, Dependencies and Maintenance Windows. For the setting Dependency Type you will now see the radio button option Select a sensor. When you click on this option, a sensor selection UI appears, where you can choose from available sensor types.

You are now able to set a Scanning Interval in the device settings via drop down menu. Additionally you have the option to set a sensor Status with the setting If a Sensor Scanning Fails.

We added a selector for device templates that you can now open in the new UI of PRTG. The Confirm button is disabled when you do not make changes to the selection. When you change the selection for device templates, you are not able to close the dialogue but have to click Confirm instead.

We fixed an issue for sensor graphs that were not correctly displayed in the new UI. For example, when you opened the Graphs tab of a sensor and used the Expand option and added one or two more channels, you would see only one channel graph in this case.

We fixed an issue where the vertical scrollbar on the Sensor List tab under Monitoring only appeared at the bottom of the page when you scrolled down. The vertical scrollbar is now visible on the whole page for the Sensor List if scrolling is necessary.

We fixed an issue that occurred in certain cases when you replaced your SSH Remote Ping v1 sensors with the successor SSH Remote Ping v2 sensors. We deprecated the SSH Remote Ping v1 sensor with PRTG version 25.2.108.1358. In this case, the SSH Remote Ping v2 accidentially would use the SSH host as device instead of the remote target, what resulted in wrong values. You could also observe that the sensor did not display any packet loss which worked with the v1 sensor before.

We fixed an issue that occurred with latest Preview 25.3.110.1297 and which could have led to broken integrations that use PRTG API v2 endpoints, like for example, PRTG MultiBoard.

You can verify the authenticity of the PRTG installer with the Secure Hash Algorithms for the following versions and release channels:

Preview 25.3.110.1311

• sha256_exe 94A77343A02D4F667A25B08C614B652D8335CD750016B033176D1B30148091F3
 
• sha256_zip C9ED8E63DCE112E3118F023092F2337DACD26A1CD43BB3D8084499323F68C57B