How to update the Kemp LoadMaster Firmware

To update the LoadMaster firmware, follow the steps below in the Web User Interface (WUI).

To obtain the latest firmware please go to our Downloads Section located here.

Step 1) Back up the LoadMaster

KEMP recommends taking a backup of the LoadMaster as a restore point which can be used if needed. To back up the LoadMaster, go to System Configuration > System Administration > Backup/Restore. Click Create Backup File.

Certificates need to be backed up separately. For instructions on how to back up certificates refer to the following article: How do I back up certificates?.

Step 2) Download the patch

  1. Log into the KEMP Support Center.
  2. Click Downloads.
  3. Select the appropriate LoadMaster type/model.
  4. Download the appropriate firmware release.

Step 3) Install the patch (Start on Standby unit if in HA)

  1. In the WUI, go to System Configuration > System Administration > Update Software.
  2. Click Choose File.
  3. Browse to and select the patch file.
  4. Click Update Machine.
  5. Follow the prompts to apply the patch.

Note: If the above Step 3 fails due to the error message "License disallows further software updates", please see this Knowledge Base Article on how to resolve this, and for more details on the LoadMaster license.

Step 4) Reboot

You will be prompted to reboot the LoadMaster. Please do so.

Step 5) Clear the browser cache

After patching, if there are any problems using the WUI, please clear the browser cache and restart the browser.

Step 6) Repeat the process for the partner unit (if applicable)

LoadMaster Highly Available (HA) pairs require each unit be patched separately. Following this process will achieve the least amount of down time since once one fail-over is required. The overall process is as follows:

  1. Patch the Standby unit via the individual IP address.
  2. Reboot the upgraded unit.
  3. Check to ensure the patched unit is back online (try to access the LoadMaster administrative IP address, which usually the eth0 IP address).
  4. Now the patch the active unit.
  5. Reboot the upgraded unit.


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Thanks for sharing the article.

DMI License Account

I use a HA pair. This was my upgrade path:
1. Update the active VLM via shared IP.
2. Reboot.
3. As soon as the upgraded VLM came back up, it became active again. I didnt do a thing.
4. Then I upgraded the standby unit via its own IP: Local administration - Update Software.

Philip O'Connor

Hello, Thank you for sharing your experience.
On the LoadMaster WUI under HA Parameters, you might have had the option Switch to Preferred Server enabled. This is normally not enabled by default. Changing it to no Preferred Host before preforming the update will prevent the unit for becoming master again. However you might wish to return to this setting after the upgrade is completed.


One question. Will the websites and exchange still be available while performing the update on the active VLM?

Edited by e.van.kruiselbergen
Stephen Wong

when I go to "software update", it shows "license disallows any further software..."


If you are using a free version for development, you cannot update you would have to backup and start again?


How long would an update on a single machine take?
We have VLM-2000 with has currently the 7.1-30-75 firmware.


Hello how do I find which model I have..
on home the appliance model is empty :

Licensed until: unlimited
Support Level:
Support Until: none
License Type:
License Status: Single Perm
Appliance Model:

Per-Olof Hagstrom

These steps do not seem like the most optimal way of upgrading an HA-pair setup, at least not from uptime perspective. Wouldn't it be better to first connect directly to the passive node, upgrade it, wait for it to come back, then fail over, and then upgrade the second unit which now is passive? Or is there a specific reason you "have to" connect to the active/shared IP?

Justin Federico


Thank you for your comment. There is no specific reason for the software upgrades to be performed from the shared IP other than this IP is the Management IP of the pair. You will have less downtime/less fail-overs if you perform the upgrade on the standby LM first. Basically it is a matter of preference as either process would be supported. As with all such maintenance we suggest that the software upgrades be performed during a scheduled window.


Hi Support,

We have LM-4000 HA pair with one as HA first mode & another as HA second mode.
When logged in to HA IP , System Status shows in Display HA second mode Device IP & Serial, this means the device with HA Second mode is Active & HA first mode device is passive?

Then which One to be upgraded first.


Justin Federico


Master/Standby has no dependence on First/Second mode. First/Second mode is simply an identifier used to tie each unit to its respective settings in the shared configuration.

In order to identify which unit is the Standby, log in to each individual IP address rather than the shared (HA) IP address. At the upper right of the screen each unit is identified as "Master" or "Standby".

Alternatively you can log into the shared (HA) IP address. The unit being accessed from the shared address is always Master so by process of elimination the other unit is the Standby.

I hope this helps to clarify the process. Thank you very much for you inquiry.

Edited by Justin Federico

As per.hagstrom pointed out, it's typically best to update the standby unit first and then reboot it. Here are my steps, and you'll notice I switch the preferred server after updating and rebooting the standby unit. This will allow for even less down time since you don't have to wait for the timeout period of the HA health checks, however I also leverage "Inter HA L7 Persistency Updates" so I essentially don't see any connection drops.

1) Update the standby unit, and in my case it's the "Second HA" unit.
2) Reboot the standby unit
3) Confirm standby unit is operational and functioning correctly after the reboot.
4) On the Active unit(this is my "First unit") , change the "Switch to Preferred Server" to the standby unit(Second HA), which will then make the Second HA unit Active, and the "First HA" unit will automatically change to standby.
5) Rinse and repeat here; so I update the First HA unit, reboot it, and then make it Active again through the "Switch to Preferred Server"