I have ver. 3 on my MacPro which runs 10.7.5 & it syncs with the Dropbox - I also have ver. 4 on my iMac and the newer versions on the iPhone5S and iPad [all software is up to date - the only old software is my MP and its apps.]. I noticed that my 1PW on my iMac, which I was updating due to vulnerabilities noticed, was not syncing via Dropbox [the appropriate file was on DB and correctly identified on all machines & versions of 1PW] - because I had a meeting to go to I changed things to iCloud sync and updated the iPad and iPhone.
It seemed not to work or sync, but i think I fixed that = but on trying to set up my 1PW on my MacPro I didn't see any way to set it up using my iCloud account - which is how I finally went to sync using the newer three devices. How do I have one place to sync to and from? using both ver. 3 and 4 of the app?? As I said, I use the MP asa main machine still = and the iMac increasingly but the iPad and iPhone are also important.