I recently saw that if you upgrade to 12.7.2 U2 or 12.5.9 U2, you can't revert to a lower version. Are there instances where I would consider reverting in the first place?
The most common reason would be that you ran into a bug and need an older version of something vital to your network.
In the case of this upgrade, I would suggest that patching this vulnerability is very important.
I would suggest looking over the release notes and seeing what the changes are, which can help you determine if they may impact you.
12.7.2 U2 Release Noteshttps://www.watchguard.com/support/release-notes/fireware/12/en-US/EN_ReleaseNotes_Fireware_12_7_2/index.html#Fireware/en-US/resolved_issues.html
12.5.9 U2 Release Noteshttps://www.watchguard.com/support/release-notes/fireware/12/en-US/EN_ReleaseNotes_Fireware_12_5_9/index.html#Fireware/en-US/resolved_issues.html
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