I have been using WD V15 and have many problems. The program keeps crashing, my.web file keeps saving as zero bytes with no data. I have raised a ticket with Xara and they are aware of this problem and have said they are working on it and an update should hopefully be out in a couple of weeks.

Is it OK to go back to V12 while I wait for this update, now I have used V15 and saved my website in V15?

A word of advise to anybody using V15. Make sure you have a backup of your data all the time, otherwise you could loose everything.