split database into front end and back end:
tools => database utilities => database splitter
this will create one database with forms/reports and the other with tables only....
now you can convert front end to approprate version per client, and keep back end in 97.....
warning: this can cause a problem of back end database corruption!
I've had this situation when we migrated from 97 to XP, and some clients were on 97 while others were on XP