XCP-ng 8.3 updates announcements and testing

[gduperrey]

Thank you everyone for your tests and your feedback!

The updates are live now: https://xcp-ng.org/blog/2026/10/05/october-2026-updates-1-for-xcp-ng-8-3-lts/

We decided not to release the xen update that was initially included in the testing phase of this update cycle. It introduced changes related to support for Windows VMs with more than 64 vCPUs; a feature that is not yet fully supported and requires further work to be completely implemented.

We therefore chose to postpone it to avoid any regressions or user confusion, aiming to release a properly finalized and documented version in the near future.

This version should have no impact on your test environments, and they can continue to operate as is. Any future xen update should have a higher version number and should install over the current one.

However, if you do not wish to keep this update on your test environments, you can downgrade using the command yum downgrade xen-*.

[bvitnik]

@gleh said:

Disable Viridian in the "Other install media" template by default. As a reminder, Windows VMs must use Windows templates.

What is the rationale for disabling Viridian? Does it have any negative effects for non Windows VMs?

[acebmxer]

@gduperrey

Just tried to install the patches pushed today to home lab. All but 1 vm evactuated from the primary host.

 },
                    "taskRef": "OpaqueRef:f56d3f5e-d41c-c8eb-3c70-4676f74de68c",
                    "message": "task has been destroyed before completion",
                    "name": "Error",
                    "stack": "Error: task has been destroyed before completion\n    at Xapi._removeRecordFromCache (file:///opt/xen-orchestra/packages/xen-api/index.mjs:1462:21)\n    at file:///opt/xen-orchestra/packages/xen-api/index.mjs:1429:18\n    at Set.forEach (<anonymous>)\n    at file:///opt/xen-orchestra/packages/xen-api/index.mjs:1428:20"
                  }

Rolling pool update.txt

VM that wouldnt migrate -

[TeddyAstie]

@bvitnik
Various reasons :

• In some niche cases, it can cause compatibility issues with guests.
• Viridian exposes additionnal attack surface e.g VSA-2025-006 and VSA-2026-031
  and given that this is generally unused for non-Windows guests, there is no good reason to expose it to the guest

For Windows guests, use of the dedicated Windows template is strongly encouraged, as it brings additional viridian flags and other tunings for better compatibility and performance.

[bvitnik]

@TeddyAstie Thanks

[acebmxer]

after multiple failed attempts and rebooted all three host. Host 1 did update and finally got host 2 and host 3 updated both via rolling pool update.

During the evacuation multiple vms failed to migrate / reboot. All showing similar errors in each console for the vms.

[jacob.becker]

@acebmxer
Had some similar Errors on 2 Arista appliances with an older Alma-Linux base (9.5).
After upgrading the image (Alma 9.6 based) the error went away - so it looks like a kernel thing

what kernel run inside your vm ?

[acebmxer]

@jacob.becker

VM were Ubuntu and Fedora distros. Ubuntu is 7.0.0-38-generic. The Fedora vms 7.2.7-200.fc44.x86_64 and 7.2.9-300.fc45.x86_64.

Had no issues with the beta test but those were done not via Rolling pool update.

[jacob.becker]

@acebmxer
Can you suspend the vm ?

If its not possible its most likely a kernel thing inside the vm.
If you can suspend the vm however, it points more to a timing/timeout issue with the migration.

[gduperrey]

We have just released security updates for xen and blktap. Full details are available on the blog: https://xcp-ng.org/blog/2026/10/13/october-2026-security-updates-2-for-xcp-ng-8-3-lts/