Dropbox announced some time ago that it would be retiring its original sync API, and it is being officially put out to pasture on September 1 to introduce a new, more secure version. This is good news for a lot of users, but people still using apps that were built on that older API will likely find those apps won't work as expected after the September 1 cut off. This includes the older v3 version of 1Password for the iPhone/iPad and 1Password Pro for iOS. While the password manager will still work in other respects, Dropbox-powered sync won't function.
These apps were pulled from the iTunes store last year to make way for 1Password version 4, which means there is no mechanism to release an update for them, but there are still plenty of people using those previous versions. For those who depend on Dropbox sync and haven't yet rolled forward to v4, 1Password developer AgileBits has announced they will be running a limited-time sale on 1Password 4 for iOS, starting at 8 AM Pacific time on August 8, and ending on August 16.
The app will sell for US$7.99, more than half off its current price. You can read their explanation of the whole situation over at their blog. While those who have stuck with the older version of 1P are certainly entitled to use it as long as they can, it's nice to see a developer taking steps to help out syncing users who are caught in an API squeeze.