The OP mentioned that he _had_ to buy the AppStore version. That was back when 1Password switched from v3 to v4. Then, they also disabled the legacy Dropbox support. They made that very transparent and also wrote[1] about it on their blog. Also note that 1Password needs you to sync via Dropbox for secondary vaults.

1. http://blog.agilebits.com/2013/08/08/1password-3-dropbox-syn...