Hello!
Thanks, I got the file. I've given it to ghazan who's the main dev, he'll have a look at making a crutch
For your question, hmm.
I suggest to do the following, if you're really, really interesting in preserving your data (I am, so...
I do this myself whenever a db update comes out).
With old profile / old miranda, download and use the MsgExport plugin (
https://wiki.miranda-ng.org/index.php?title=Plugin:Msg_Export/en ) and export all of your history into json files. (Miranda options->History->Message export->General-> "Use JSON format for export - check" + "Use UTF8 in new files - check", max column width - set to 0, and configure a good default path.)
Then in the "Contacts" tab, make sure all (or relevant) contacts are checked, and then press "export all history" button.
It will take some time depending on your profile size, but it will save all histories into human readable jsons.
Afterwards, move this folder somewhere, then do a compact + upgrade to new version of libmdbx, and then do this same export again.
Afterwards, run a comparison of the exported files.
(I suggest using Total Commander in windows, excellent file commander from
http://www.ghisler.com/ ), navigate to the post-compaction export folder in the left pane, and to the old, pre-compaction export in the right pane, then in Total commander's menu -> Commands->Synchronize dirs,
select "Asymmetric - check, by content-check, ignore date-check" and make sure the "show" section has left arrow, non-equal sign and right arrow enabled.
Then run "compare". If you have lost no data or if no corruption occurred, the comparison will show an empty window, i.e. all the files are the same.
If there are differences, simply double-click the row with the differences which will bring a side by side comparison of the file contents where you can usually very easily see what the difference is, and whether or not it's okay. (sometimes it could be like a removed newline or so).
Based on the results of the above comparison, you can then decide to either stay on the upgraded version - or wait for a fix and keep using the old mdbx for now.
I'm a bit obsessed with making sure my data is safe so this is what I do. It is some manual work but in the end it's not too bad and it ensures integrity of irreplaceable data which, if lost, would make me very sad :p