Guest OS update for Cloud Services (extended support)

Question

Guest OS update for Cloud Services (extended support)

Sergei Kamnev 5

Today we can see that Guest OS WA-GUEST-OS-7.61_202602-01 has become active to use. However, there is -02 Guest OS not active: WA-GUEST-OS-7.61_202602-02. Usually in the past it meant that -01 Guest OS was incomplete/wrong, so -02 should be used instead. Can someone at MSFT make sure that -01 Guest OS is correct to switch to? ideally I'd see -02 Guest OS active or (the best) latest Guest OS is permitted to use (WA-GUEST-OS-7.62_202603-01)

Himanshu Shekhar 5,235 Reputation points Microsoft External Staff Moderator

2026-03-26T09:47:20.8166667+00:00

Hello [@Sergei Kamnev],

The -01 / -02 suffix shows multiple revision builds within the same Guest OS release. When a Guest OS version is marked Active in the portal, it means that specific build has completed validation and is approved for customer use. An additional -02 build may exist internally or be staged, but if it is not shown as active, it is not yet approved for deployment.

At this time, WA‑GUEST‑OS‑7.61_202602‑01 being active indicates it has passed Microsoft validation and is safe to switch to. The presence of a non‑active ‑02 does not automatically imply an issue with ‑01.

Regarding WA‑GUEST‑OS‑7.62_202603‑01, Guest OS versions become selectable only after completing phased rollout and validation. Until it is explicitly marked active, it is not supported for use.

Best practice remains:

Use only Guest OS versions marked Active in the portal

Or set osVersion="*" to automatically consume the latest Microsoft‑approved Guest OS once it becomes available

Microsoft publishes and supports only validated Guest OS versions, as documented here:

Azure Guest OS releases and SDK compatibility matrix - https://learn.microsoft.com/en-us/azure/cloud-services-extended-support/cloud-services-guestos-update-matrix

If there is any change in status (for example, activation of ‑02 or 7.62), it will be reflected there.

If you have any further queries, let me know. If the information is helpful, please click on Upvote and Accept Answer on it.
Sergei Kamnev 5 Reputation points

2026-03-26T10:37:19.7166667+00:00

Thank you for citing documentation. Meantime, I'm too long time working with Cloud Services and remember cases when faulty Guest OSes were made active with serious consequences. That's why I'm monitoring Guest OS releases on daily basis and here what I can say.

Last Guest OSes as of 2/12/2026: this is when February release has appeared on the list for the first time

Version Family IsActive IsDefault Label

WA-GUEST-OS-7.59_202512-01 7 True True Windows Azure Guest OS 7.59 (Release 202512-01)

WA-GUEST-OS-7.60_202601-01 7 False False Windows Azure Guest OS 7.60 (Release 202601-01)

WA-GUEST-OS-7.61_202602-01 7 False False Windows Azure Guest OS 7.61 (Release 202602-01)

=========

Last Guest OSes as of 2/13/2026:

Version Family IsActive IsDefault Label

WA-GUEST-OS-7.59_202512-01 7 True True Windows Azure Guest OS 7.59 (Release 202512-01)

WA-GUEST-OS-7.60_202601-01 7 False False Windows Azure Guest OS 7.60 (Release 202601-01)

WA-GUEST-OS-7.61_202602-01 7 False False Windows Azure Guest OS 7.61 (Release 202602-01)

WA-GUEST-OS-7.61_202602-02 7 False False Windows Azure Guest OS 7.61 (Release 202602-02)

We can see that just after one days of releasing -01 version MSFT releases -02 version. Historically, it indicated serious problems with -01 release or major vulnerability fix. That's why I ask MSFT persons who indeed know the reason of appearing -02 one day after -01: is -01 applicable and will not crash our Production site? I have to ask it as we had such issues in the past.

P.S. From my daily monitoring of the list of Guest OSes I came to the conclusion that a person or process responsible for "IsActive" flag is just making "True" for next version on the list. This is the main reason of my concern.

And I don't believe that -02 Guest OS didn't complete rollout and validation during 42 days. I will see tomorrow: if they were released within one day then validation should also complete within one day.
Himanshu Shekhar 5,235 Reputation points Microsoft External Staff Moderator

2026-03-26T12:45:56.3033333+00:00
Sergei Kamnev - To clarify based on Microsoft’s current Guest OS release and validation process for Azure Cloud Services (Extended Support):

The -01 / -02 suffixes represent revision builds within the same Guest OS release, not an automatic indication of a faulty or withdrawn build.

A Guest OS version marked IsActive = True means that this specific revision has completed Microsoft’s validation and phased rollout checks and is approved for production use.

The presence of a newer revision (for example, -02) that is not Active does not imply an issue with the Active -01 build. Non‑active revisions are not supported or deployed until they explicitly pass validation and are marked Active.

If a critical issue were identified with an Active Guest OS, Microsoft would either activate a newer revision or block the earlier one. Neither action has occurred for WA‑GUEST‑OS‑7.61_202602‑01.

Note - WA‑GUEST‑OS‑7.61_202602‑01 is the latest validated, supported, and production‑safe Guest OS.

Microsoft‑recommended best practice remains:

Use only Guest OS versions marked Active, or

Set osVersion="*" to automatically consume the latest Microsoft‑approved Guest OS once it becomes Active.

Official reference: Azure Guest OS releases and SDK compatibility matrix
Sergei Kamnev 5 Reputation points

2026-03-26T13:05:35.5933333+00:00

Okay. I will not update Guest OS and will continue to monitor. If your clarification is correct then somewhere within a week or so we should see -02 release becoming Active. Meantime if it will become Active in 4 weeks then I will understant that your explanations are wrong (because in 4 weeks March release should be out, WA‑GUEST‑OS‑7.62_202603‑01 (which is on the list already, but IsActive = false).

I will ask but suppose you won't be able to answer: what updates included into -02 but not in -01.

P.S. your reference on compatibility matrix doesn't work because the matrix doesn't reflect actual state. Moreover, in the past it could list -01 OS, which could not be used because -02 OS was used. But no one cared.
Himanshu Shekhar 5,235 Reputation points Microsoft External Staff Moderator

2026-03-26T15:18:02.8566667+00:00

Continue using the currently Active Guest OS and do not take any action based solely on the presence of -01 or -02 versions in the list.

The -02 Guest OS is not a feature upgrade over -01; it is a servicing / superseding build released as part of Microsoft’s internal staged rollout and validation process.

There is no fixed or guaranteed timeline for when -02 becomes Active. In some cases, -01 may never be activated if -02 supersedes it during validation.

The exact changes between -01 and -02 are not customer‑published, as these builds roll up internal quality and reliability fixes rather than customer‑visible features.

The compatibility matrix reflects supported states, not real‑time activation or rollout sequencing, which is why mismatches can be observed historically and today
Himanshu Shekhar 5,235 Reputation points Microsoft External Staff Moderator

2026-03-30T08:46:55.8+00:00

Hello @Sergei Kamnev, Just checking if provided response was helpful! please let me know if you have any queries.
Sergei Kamnev 5 Reputation points

2026-04-07T09:52:59.0466667+00:00

Hello.

Don't hurry. As I understand, Guest OS cycle is 4 weeks, so this problem will be clear after a month or so.

As of today, 4/7/2026, I can see that WA-GUEST-OS-7.61_202602-02 is still not active. According to you, once testing of the version is completed, it will be available for use. I'm waiting for this event. Just reminding, that -02 version appeared on the list of Guest OSes just one day after -01 appearance. It would be logical that testing completes also within one day after -01 testing completed. So far 12 days passed, still not active. Waiting...
Sergei Kamnev 5 Reputation points

2026-04-14T09:41:29.5466667+00:00

Hello Himanshu. I know all that, it sounds reasonable if we didn't have problems with 01-02 in the past. Nevermind, while WA-GUEST-OS-7.61_202602-02 is still not active, we can see that next release, WA-GUEST-OS-7.62_202603-01, is already active so we will switch right into it. The thread can be closed. Note: GuestOS matrix still lists latest version as WA-GUEST-OS-7.60_202601-01

1 answer

Your answer

Himanshu Shekhar 5,235 Reputation points Microsoft External Staff Moderator

2026-03-26T09:47:20.8166667+00:00

Hello [@Sergei Kamnev],

The -01 / -02 suffix shows multiple revision builds within the same Guest OS release. When a Guest OS version is marked Active in the portal, it means that specific build has completed validation and is approved for customer use. An additional -02 build may exist internally or be staged, but if it is not shown as active, it is not yet approved for deployment.

At this time, WA‑GUEST‑OS‑7.61_202602‑01 being active indicates it has passed Microsoft validation and is safe to switch to. The presence of a non‑active ‑02 does not automatically imply an issue with ‑01.

Regarding WA‑GUEST‑OS‑7.62_202603‑01, Guest OS versions become selectable only after completing phased rollout and validation. Until it is explicitly marked active, it is not supported for use.

Best practice remains:

Use only Guest OS versions marked Active in the portal

Or set osVersion="*" to automatically consume the latest Microsoft‑approved Guest OS once it becomes available

Microsoft publishes and supports only validated Guest OS versions, as documented here:

Azure Guest OS releases and SDK compatibility matrix - https://learn.microsoft.com/en-us/azure/cloud-services-extended-support/cloud-services-guestos-update-matrix

If there is any change in status (for example, activation of ‑02 or 7.62), it will be reflected there.

If you have any further queries, let me know. If the information is helpful, please click on Upvote and Accept Answer on it.
Himanshu Shekhar 5,235 Reputation points Microsoft External Staff Moderator

2026-03-26T12:45:56.3033333+00:00

Sergei Kamnev - To clarify based on Microsoft’s current Guest OS release and validation process for Azure Cloud Services (Extended Support):

The -01 / -02 suffixes represent revision builds within the same Guest OS release, not an automatic indication of a faulty or withdrawn build.

A Guest OS version marked IsActive = True means that this specific revision has completed Microsoft’s validation and phased rollout checks and is approved for production use.

The presence of a newer revision (for example, -02) that is not Active does not imply an issue with the Active -01 build. Non‑active revisions are not supported or deployed until they explicitly pass validation and are marked Active.

If a critical issue were identified with an Active Guest OS, Microsoft would either activate a newer revision or block the earlier one. Neither action has occurred for WA‑GUEST‑OS‑7.61_202602‑01.

Note - WA‑GUEST‑OS‑7.61_202602‑01 is the latest validated, supported, and production‑safe Guest OS.

Microsoft‑recommended best practice remains:

Use only Guest OS versions marked Active, or

Set osVersion="*" to automatically consume the latest Microsoft‑approved Guest OS once it becomes Active.

Official reference: Azure Guest OS releases and SDK compatibility matrix
Sergei Kamnev 5 Reputation points

2026-03-26T13:05:35.5933333+00:00

Okay. I will not update Guest OS and will continue to monitor. If your clarification is correct then somewhere within a week or so we should see -02 release becoming Active. Meantime if it will become Active in 4 weeks then I will understant that your explanations are wrong (because in 4 weeks March release should be out, WA‑GUEST‑OS‑7.62_202603‑01 (which is on the list already, but IsActive = false).

I will ask but suppose you won't be able to answer: what updates included into -02 but not in -01.

P.S. your reference on compatibility matrix doesn't work because the matrix doesn't reflect actual state. Moreover, in the past it could list -01 OS, which could not be used because -02 OS was used. But no one cared.
Himanshu Shekhar 5,235 Reputation points Microsoft External Staff Moderator

2026-03-26T15:18:02.8566667+00:00

Continue using the currently Active Guest OS and do not take any action based solely on the presence of -01 or -02 versions in the list.

The -02 Guest OS is not a feature upgrade over -01; it is a servicing / superseding build released as part of Microsoft’s internal staged rollout and validation process.

There is no fixed or guaranteed timeline for when -02 becomes Active. In some cases, -01 may never be activated if -02 supersedes it during validation.

The exact changes between -01 and -02 are not customer‑published, as these builds roll up internal quality and reliability fixes rather than customer‑visible features.

The compatibility matrix reflects supported states, not real‑time activation or rollout sequencing, which is why mismatches can be observed historically and today
Himanshu Shekhar 5,235 Reputation points Microsoft External Staff Moderator

2026-03-30T08:46:55.8+00:00

Hello @Sergei Kamnev, Just checking if provided response was helpful! please let me know if you have any queries.
Sergei Kamnev 5 Reputation points

2026-04-07T09:52:59.0466667+00:00

Hello.

Don't hurry. As I understand, Guest OS cycle is 4 weeks, so this problem will be clear after a month or so.

As of today, 4/7/2026, I can see that WA-GUEST-OS-7.61_202602-02 is still not active. According to you, once testing of the version is completed, it will be available for use. I'm waiting for this event. Just reminding, that -02 version appeared on the list of Guest OSes just one day after -01 appearance. It would be logical that testing completes also within one day after -01 testing completed. So far 12 days passed, still not active. Waiting...
Sergei Kamnev 5 Reputation points

2026-04-14T09:41:29.5466667+00:00

Hello Himanshu. I know all that, it sounds reasonable if we didn't have problems with 01-02 in the past. Nevermind, while WA-GUEST-OS-7.61_202602-02 is still not active, we can see that next release, WA-GUEST-OS-7.62_202603-01, is already active so we will switch right into it. The thread can be closed. Note: GuestOS matrix still lists latest version as WA-GUEST-OS-7.60_202601-01

Answer 1

Himanshu Shekhar 5,235 Microsoft External Staff Moderator

Thanks for the update. To reiterate, there is no fixed testing or activation timeline tied to when a ‑02 revision appears. A Guest OS revision becomes usable only when it is explicitly marked Active, regardless of how long it has been listed. The fact that WA‑GUEST‑OS‑7.61_202602‑02 is still not Active simply means it has not been approved for production use. Until that status changes, WA‑GUEST‑OS‑7.61_202602‑01 remains the latest supported and validated option.

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Guest OS update for Cloud Services (extended support)

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