Don't understand your answer
You have just sent me this answer. I don't understand it:
This is still possible and in the same was as it was in 2.x, via export
I am now beginning to understand this mess. The problem is caused by your misleading messages and confusing behaviour during the conversion. If you had explained and implemented all this satisfactorily in the first place, this mess would never have occurred.
I have now saved my Misty file under another name, after the conversion. I had to edit it all over again as all yesterday's edits were lost. (Fortunately, I had an up-to-date printout.)
In my irritation, I tried to create the mp3 file in the wrong way. That was my error, so you can disregard my message about that.
Maybe things are working now. But I am still extremely dissatisfied with the way you handled the upgrade. I have been a software professional for 40 years, specializing during recent years as an architect in upgrades, usability and documentation, and this was not a satisfactory handling of an upgrade. (I have also been a programmer and a tester.)
I hope your next upgrade is managed better. Please forward my feedback to your architects.