1Password 4 was created in 2012 and has not been under active development since 2014. It supports OS X Mountain Lion and Mavericks, so it has compatibility issues with recent operating system (OS) and web browser releases and won't be receiving updates in the future. Since we use 1Password to help us be more secure, it's important to stay up to date with not only 1Password, but also OS and browser updates, which contain important security fixes.
If you've purchased 1Password for Mac version 4, you're entitled to use it on all of your compatible devices indefinitely, and version 6 is a free upgrade. And if you'd like to always have the newest version, along with many other benefits, you can sign up for a 1Password.com membership. This works with macOS Yosemite, El Capitan, Sierra, and High Sierra, and supports the latest versions of major browsers.
All Macs that can run Mavericks can upgrade to El Capitan (system requirements) — and many can upgrade to High Sierra. But if you're unable to upgrade, you can still use 1Password 4 in a limited fashion, bearing in mind the security risks, and that you may encounter some issues introduced over time:
Google is no longer providing Chrome updates on OS X Mountain Lion and older, and Mozilla has done the same with Firefox.
While 1Password 4 has benefitted from many improvements we've continued to make in the 1Password extension in recent years, future versions of the 1Password extension that we're working on will require 1Password 6 or later.
Safari is currently the best solution for 1Password integration in the browser on macOS 10.9 Mavericks. The code signature identity has not changed and we don't have any known incompatibilities. While we don't test the 1Password extension with Safari 7 any longer, Safari has pretty good standards support, so the 1Password extension continues to work there without significant issues.
1Password 4 cannot connect securely to Chrome 58 or higher, as Google has changed their code signature as of May 2017, so 1Password 4 can no longer validate it. Upgrade 1Password/macOS, or disable the security check in Preferences > Advanced (not recommended).
As of 1Password 4.6.9 of the browser extension, 1Password 4 will no longer be able to communicate with Firefox; 1Password 6 for Mac, 1Password 4 for Windows, or 1Password 6 for Windows is required.
Firefox 57 is slated for release in November 2017, at which time the old approach to browser extensions will no longer be allowed. We have made the leap to the new approach well ahead of the Firefox 57 stable release since many 1Password users are also using pre-release versions of Firefox and users of the stable Firefox with the latest 1Password releases can already use the new approach as well.
It's a common refrain, but the most important thing you can do for your digital security is to keep software up-to-date. This applies to your operating system, your browser, and any other programs including 1Password and the browser extension. And of course, keeping up to date with 1Password allows you to continue to get the most out of it with new features, bug fixes, and improved browser compatibilities.
If you purchased a license from the AgileBits Store, you'll need to download the 1Password 4 app.
If you purchased through the Mac App Store, you'll need to install it from the "Purchased" tab in the App Store on your Mac with the Apple ID used for the purchase.
The 1Password extension can be downloaded for each browser from the 1Password extension download page.