The definitive statement about the upgrade to 1Password4 on iOS starts with "If you use 1Password 3 for iOS and Dropbox sync ..."
OK, cool, but how do I know if I am? I've been using 1Password3 on my iPhone and on my Mac for quite a while -- I certainly don't recall the original setup.
I can't find anything referencing "sync" under preferences on either, nor any hint about what I might look for in DropBox (which I also use).
( Mac version: 3.8.21; iPhone version: 3.7.2 )