Somewhere between upgrading WordPress and (possibly) upgrading MySql database, all the non latin characters got corrupted. This included my Russian, Spanish, French and possibly Esperanto writing. Basically, anything in UTF-8 that is not in latin-1.
The partial solution was go into database administration and changing the text columns collation order to Unicode. Unfortunately, that only fixed the new entries and not the old ones. So, I have to compare latest export with the older backup (which I take before every upgrade) and reconstruct entries from that.
I don’t know if that means reedited entries will get pushed into RSS feed again. Hopefully not, but if it does, this is the advance apology.