Why don't we just turn off MOZ_BLOCK_PROFILE_DOWNGRADE?

Nomis101 🐝 Nomis101 at web.de
Fri Jul 5 13:04:06 UTC 2019

Am 05.07.19 um 10:09 schrieb Mark Banner:
> I would just like to point out that whilst "you" personally (not just talking about you, but those responding here in this manner) haven't seen any issues, that doesn't mean to say there aren't.

Sure, that's undoubtedly true. But if I search the web for "thunderbird downgrade issue", I only find support questions or HowTo's about how to downgrade Thunderbird.
So, downgrading Thunderbird seems a thing people are doing, mostly without issues.

> For example, this is one I hit during Hello development: https://bugzilla.mozilla.org/show_bug.cgi?id=1092090
> It is a little while ago, but I think that would have affected any user's indexeddb database(s). Though it probably wasn't so widely in use at the time.

I was speaking about Thunderbird in specific, your bug is about Firefox. In the bug you were talking about storage/persistent/chrome. I know this is an important
thing for Webbrowsers, is it also used in Thunderbird? What does this store in Thunderbird that can be corrupted?

> Developers can use --allow-downgrade to skip the protection.

I know about that switch. For developers this might work. But I'm more concerend about the regular user. I would prefer a dialog at the first start of a new Thunderbird
version saying something like "Thunderbird has enabled a downgrade protection. If you start Thunderbird xy, your profile will be updated and will not work anymore with older
versions of Thunderbird." And then you can cancel and use your older version or accept and use the newer version. Additionally a about:config accessible pref would
be nice, so you can switch this off at your own risk. Instead of hardcoding it. Currently there is no indication at all if you start the application the first time, that it
will be difficult to go back.

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