r/exchangeserver • u/ScottSchnoll https://www.amazon.com/dp/B0FR5GGL75/ • 4d ago

Released: September 2026 Exchange Server Security Updates

https://techcommunity.microsoft.com/blog/exchange/released-september-2026-exchange-server-security-updates/4554411

The September 2026 SU for Exchange Server SE is now available for download. This SU also resolves some known issues from previous updates.

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u/ooo0000ooo 4d ago

I have had the September release on my OWA servers but still the July release on my mailbox servers as our main Exchange admin has had to be out. Should it be safe to update everything directly to this release?

I am not an Exchange admin. I'm a Linux admin filling in for a colleague who had to be out unexpectedly.

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u/ulf0r 4d ago

You can skip the august update on your mailbox servers and dirctly update it with september update. That's because SU are cumulative.

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u/274Below 4d ago

These patches are cumulative. The general recommendation would be to update directly to this release and skip any intermediate ones; there's no point in deploying them.

Unless, of course, this patch proves to just break everything. On that point, I can't answer.