By what version the file was created and whether or not it also could be read by that version was not in my focus. Having investigated a bit I can tell you that it was originally created by Антон Дербенёв, generated and edited with LibO4.2.5**.1** (a release Candidate!) and edited by 228 cycles over a vast amont of time. The exactly same version I cannot get “Portable” and wouldn’t install regularly for this test.
Lupp, that’s actually my first and last names, so yep, I edited it. Also, I started the series long ago, then copying & renaming it, so 228 cycles it’s from 2005 I think 
Well, maybe 4.2.5*.1*. I use RCs if previous release is too buggy for me. And I do report bugs I can explain. Well, anyway I didn’t ask which version, I asked what to do if this will happen again (with other version) 
Sorry! There may occur many errors we stand amazed by. I simply have to admit my lack of needed competences in this case. And, yes; there will be errors again I will not know a remedy for. As I am working with the software (and its perdecessors) for about 20 years now and never have experienceec a disastrous loss, I am rather confident. And I keep my fingers crossed for you.