Users who upgrade to MacOS 10.14 (Mojave) and Safari 12 may be startled to see the following warning when they try to install AdBlock from our website: "Safari no longer supports the unsafe extension "AdBlock."


"Safari no longer supports the unsafe extension" warning


AdBlock is still safe to use

First, AdBlock hasn't suddenly become unsafe to use. The warning is Apple's way of notifying users that an extension is built on an older way of developing and distributing Safari extensions that Apple is phasing out.


Legacy extensions such as AdBlock run inside Safari, and can be installed from the developer's website or the Safari Extensions Gallery. With MacOS Mojave and Safari 12, Apple now requires developers to build "Safari App Extensions" instead—extensions bundled with native Mac applications, installed exclusively from the Mac App Store.


What does the move to "Safari App Extensions" mean for me?

As with most big changes, there is good news and bad news.


The good news for users is that Safari App Extensions are faster, more secure, and lighter on computer memory and processor performance than legacy extensions are.


The bad news comes in three parts.


First, legacy extensions you installed directly from the developer's website will be disabled the first time you open Safari 12.


Second, even legacy extensions you install from the Safari Extensions Gallery will stop working sometime in 2019.


Finally, converting legacy extensions to the new Safari App Extensions platform won't be easy, for a variety of technical reasons we won't get into. Some developers, particularly developers of free extensions, may decide it just isn't worth the effort. You may find some of your favorite extensions don't survive the transition.


How is AdBlock being affected?

Apple isn't just removing support for the old way to develop extensions. With MacOS Mojave, Apple is also replacing the old way of blocking ads with its newer content blocking method. (See the Safari Extensions section here for more technical detail: https://developer.apple.com/safari/whats-new/.) That represents a lot of change to absorb all at once, for us and for our users.


AdBlock for Safari is not going away. Some things will be different, however. We are preparing for the arrival of MacOS Mojave and Safari 12 in two steps to minimize disruption to our users.


Step 1: Create a new AdBlock for Safari App

Our brand-new AdBlock for Safari app is available now in the App Store. Learn more about the new AdBlock app.


Step 2: Make content blocking the only way to block ads in the legacy extension

Content blocking was introduced with Safari 9 on both MacOS and iOS. The good news is that it blocks more kinds of ads more efficiently. The bad news is that it imposes significant limitations on ad blockers that the old way doesn't.


In the current version of the AdBlock extension, users may choose to block ads the old way or the way that uses content blocking. Sometime in September, we will release an update that removes the old method entirely. Learn more about the September update.


Can I still use the AdBlock extension with Safari 12?

Maybe.


If you installed AdBlock from the Safari Extensions Gallery (the most common method), you can continue to use it after upgrading to Safari 12. It will be disabled the first time you launch Safari, but you can enable it again in Safari Extensions preferences.


If you installed AdBlock from our website or sideloaded the .safariextz file, you will not be able to use AdBlock after you upgrade to Safari 12. You will need to install it from the Safari Extensions Gallery instead. Just click through the warnings you'll receive during installation.


The AdBlock for Safari extension will stay around as long as the Safari Extensions Gallery does for compatibility with older versions of Safari. Please note, however, that we may decide to stop developing new features for it at some point.


We encourage our Safari users to give the new AdBlock app a try now. All Safari 12 users will need to move to the app by the end of 2018.