I have a copy of 1Password, version 3.8.22 and my license for version 3 doesn't work.
The app gives me a warning: The license key you entered is for an older version of 1Password. Please upgrade your license to receive a new key.
The license is for version 3, and on the support page it says:
When you purchase 1Password, your license for the purchased version will never expire and you will receive all point updates for free.
So the license for version 3 should work for version 3.8.22 as well.
1Password Version: 3.8.22
Extension Version: Not Provided
OS Version: OS X 10.10.4
Sync Type: Not Provided
KB Article: license-requirements