Linux is something of a mess. But fundamentally you can not go backward with a profile. The version numbers of Thunderbird have to increase.

I would also suggest "importing" the profile using the import tool instead of messing in replacing the .thunderbird folder. It is nothing like as simple as it used to be and the import wizard will be seeing improvements around some of the gotchas. The old slap her in (.thunderbird) and all will be good will not. Over time it is becoming less likely for copying a .Thunderbird to be successful. This may be even further impacted with the settings sync that comes with V115 in a few months.

From documentation and other users I have been told this restore procedure is correct: 1) On the new machine you open Thunderbird for the first time without making an account. That will force Thunderbird to create .thunderbird 2) You overwrite the created .thunderbird with your backup.

What documentation? Please post a link.

You should not run Thunderbird on the new computer to create a .thunderbird directory. When copying over the backed up .thunderbird directory from the old computer they will get merged. This probably messes things up. Instead just copy over the backed up .thunderbird directory, and make sure there is no newly created .thunderbird directory there yet.

I believe it is best if the Thunderbird version I restore to is the same or a newer version than the one the backup comes from.

Correct.

However a version that new can be hard to find in a main repo and sometimes it seems to go well in spite of the backup is coming from a newer version.

You can always download and use the latest release version from https://www.thunderbird.net/ This way you're always running the latest version, get automatic updates, and don't have to wait for the distribution provided version is catching up.

So my question is when it will go well and when not.?

It depends. What versions are we talking about specifically?

Do we have a list somewhere so we can see how much older versions we can restore to from what and still be completely sure that it will do no damage to the mail database.?

As a rule of thumb, you can always upgrade a profile from one major version to the next, e.g. from v91 to v102.

Will Thunderbird come up with a warning or reject the database if it is too new to be handled 100% safely.?

No.

Or how can I know for sure.?

If you're coming from a very old version you'd have to do multiple updates from one major version to the next, and not jump versions.

I am trying to make a strict and bulletproof procedure

Good luck with that.

Matt

Thank you for your answer. Yes, and Thunderbird is a bit of a mess. If Thunderbird made a new parallel lean version, just a mail client without all the historic extensions to care about, I would choose that.

christ1

Thank you for your input.

You are right I can always find the newest version but it might not be tested well enough with the Linux distro. And if you want the version that is built into the distro you might have to go a long way back from the newest.

In my case I was thinking about going back from 102.4.2 to 78.13.0

Instead I have found a 102.8.0 in a test repo I intend to use.

However the more I dig in, the worse it seems to be in the future. The procedure is changing and it gets even more complicated. Lately I ran into 'lock' (symbolic files) in .thunderbird and I can't copy them to USB-stick. Maybe I am not supposed to, it just feels unsafe the way things are changing.

In order to obtain freedom I am seriously thinking about converting my whole mail database into files.

Here is the documentation you asked for:

https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer https://www.technewstoday.com/how-to-backup-and-restore-thunderbird/