FWIW I upgraded to Parallels 19 and had a couple of issues which may or mat not to related to the upgrade:
A Uk investment (AUD is default currency) was not converting correctly, but deleting the multiplier and inserting again seemed to do the trick.
When activating Fund Manager graph pre-existing settings for date range and vertical access range would not save. I tried to isolate this gremlin, but in the process seemed to have fixed it.
Good news as far as I can see all is working well now, ... so if you have any gremlins upgrading to Parallels 19 these should be fixable.