akonadi/KDE PIM backup/restore

Hi,

Does anyone have a good overview what of the various *rc and other files under ~/.config, ~/.local/share, ~/.kde/share/config, ~/.kde/share/apps and possible ~/.cache one should backup if one wants to be able to restore a working Kontact/KMail set-up - accounts, folder settings, filters, UI customisation etc?

What files hold crucial information, and which ones derived/downloaded data that will be regenerated anew after a restore?

If this has changed from KDEPIM4 -> KDEPIM5, what are those changes?

I'm mostly interested in KMail (handled via Kontact); I think that backups of its configuration will probably contain most if not all of the crucial information for the other PIM components as well?

Application: migration to another account or host, and where relevant, being able to back out of an intemptestuous/premature version update.

It'd be very reassuring if someone from the dev team could corroborate the information if it doesn't come from a PIM developer already.

The backup command I've compiled myself from educated guesses looks like this (executed in $HOME):

tar -cjf "${ARCHIVE}"  .kde/share/config/{foldermailarchiverc,kaddressbook,email,mail,knode,kontact,kmail,akonadi,kresource}* \
	.kde/share/apps/{kaddressbook,kabc,knode,kmail,kontact}* \
	.local/share/akonadi* \
	.config/akonadi

but I've never actually tested whether this does the trick (and doesn't include a lot of useless ballast).

Thanks,
R.