Two bits of good advice there!
I've been making sure to install new Kobo Desktops when they are released with the WiFi; and yes... unless you want to be on bleeding edge, stay back level on Calibre
Tim; any way you could add some checks into the Kobo device module and present a message suggesting that the DB is back level and it should be upgraded? Maybe even a check box in the Kobo interface that would (by default) produce an error message for a downlevel database?
Peter