can you please elaborate?
you talk about an upgrade yet the topic is about merging databases..
Anope-1.8.0 should be able to read the database written by anope-1.7.14 and save it as a 1.8 DB, after which 1.7.14 won't be able to read it again however..
As for merging databases.. the 2 databases you want to merge should be saved by the same version of anope and you should also use the merge tool that came with that version of anope... so if one of the databases is 1.8 and the other is older i recommend loading the older database in 1.8 just so it gets updated and then using this db in the merge...