I got the email regarding 5.1.. checked for software updates.. it says I am current... using 4.4.3 I have not yet installed Yosemite... is that the difference?
Yes.
Hi @Migknits,
Yep, 1Password 5 requires OS X Yosemite.
The in-app updater won't display the v5 update if you're using Mavericks since it's not compatible with your Mac.
Please let us know if you have any other questions. We're always happy to help!