It is not a documented method. It is fine for those with sufficient knowledge.
We have a convention to use Update for update of /e/OS version and Upgrade for Upgrade of Android version.
OTA Upgrades are offered for official builds but no upgrade package has been prepared yet for fp5.
So the OTA_PACKAGE linked is an Update package but it is unknown to me the result of applying this a-14 update over T, my expectation is that the update would likely fail with an error message, idk.
My preferred method to upgrade FP5, having dynamic partitions, is by the regular Fastboot ROM.
Typo ?? You ask community and link official Install images. “Install only” Fastboot ROMs are identified here with leading IMG- – no sideload of any IMG-filename.zip.
However a community IMG-filename.zip could be used to fresh install, full format data, with change of Android version to a14. The community builds cannot be locked.
We do not know exactly how far the community an official builds diverge. It is not recommended to change official to community without format data.
Is this a locked or unlocked phone, FairphoneOS or /e/OS ?? Vendor in advance of Android ?? … idk or perhaps Vendor June 2024 ??
Edit ater 24 hours. This thew me at first sight, Vendor June 25 would have to be a different phone from the one we spoke of above. This must be in error.
Please check this thread (answered) Install /e/ on FP5 with newer Security Patches