Sql DB opened with wrong version

Our client opened their Fin 3.01b SQL DB with 3.7. they could not open in 3.01 anymore . I changed the field databaseversionno in the dbproperties table from 17 back to 12 and they could access the database. However they cannot delete lines as in the payment journal using mouse clicks and keyboard. they get the “do you want to delete line or lines” confirm and they say OK and the confirm closes and nothing is deleted. They can go to edit >> select all and then hit delete key, get confirm, ok it, and all lines are deleted. Is there something else I need to modify in the database without having to do a complete backup and restore (14 gigs)? What if i installed 3.7 clients on every station? (they are upgrading soon anyway) thanks for any help

I think You better hurry up installing 3.70 if possible.