Reverting back to old firmware

How long has this been around?
I just noticed it as I was fiddling around.
When asked to upgrade → have a problem → Revert Firmware
Is this only available via selecting upgrade with an older version?

/edit - any chance of getting a “revert app”?
/edit 2 - Just noticed a post from March 28th>

UPDATE-1 (3/28): I literally have next to zero playback footage since upgrading to this firmware release. Successfully rolled my own cameras back to v4.10.3.40 via the microSD root file copy method. Shortly thereafter, I discovered the firmware “REVERT” function embedded within the “HAVE TROUBLE” area of the firmware upgrade facility. Thanks so much for this! I’ve reverted all of my remote cameras to the .40 code and have verified that playback footage is once again being logged accurately.

Why haven’t we been telling all the people with Pan Cam problems about this?

Noooo - Buy an SD card, copy demo.bin file, hold down that darn little button, flash ? Or mash a revert button?

Seems like mashing a revert button would be easier and less headache. There must have been a dozen people threatening to toss their pan Cams because they don’t have an SD card.