[Update, September 2018: See our support document for more information on this change by Apple and what it means for Safari users.]

Ah. From https://developer.apple.com/safari/whats-new/:

Removed Support for Developer-signed .safariextz Safari Extensions

Support for developer-signed .safariextz Safari Extensions in Safari 12 on macOS has been removed. They no longer appear in Safari preferences and cannot be enabled. On first launch users will receive a warning notification and these extension will not load.

and

Deprecated .safariextz-style Safari Extensions

Support for .safariextz-style Safari Extensions installed from the Safari Extensions Gallery is deprecated with Safari 12 on macOS. Submissions to the Safari Extensions Gallery will no longer be accepted after December 2018. Developers are encouraged to transition to Safari App Extensions.

So that's going to be the end of the Safari connector, at least in the short term.

A Safari App Extension is only possible if you have an app distributed through the Mac App Store, which isn't currently a possibility for Zotero for technical reasons. And I believe you can't really have apps with no functionality that are only used to distributed Safari extensions, though we'll look into how flexible Apple's guidelines are there.

So, we're going to have to think about this, and we'll post back if we have any updates. For now, if you use the Safari connector, you indeed will want to avoid 10.14 Safari 12.

Allow me to interject that this is an Apple policy change that affects many programs that interact with Safari. This is not limited to Zotero. Further, Apple has policies that make the placement of Zotero connectors, extensions, etc. on their Store difficult -- not the least of which is that there can be a lengthy interval between submission and acceptance. For things that are frequently updated or improved (like Zotero's extensions) the Apple-based delays make impractical getting users to have the current versions of Zotero connection software. My hope is that Apple will realize the problems created by this new policy and will find a way to keep the policy 's security benefit but allow external softwareto interact with Safari.

Thanks!

Thanks, @GinaGottardo. (It's also worth mentioning that the current error message is totally inappropriate. This is a policy change on Apple's part. Extensions using their previous framework — which work the same as extensions in Chrome and Firefox — didn't suddenly become unsafe.)

I've updated my post above. This affects Safari 12, which will be available for Sierra and High Sierra as well, so it's not just 10.14. We'll update the download page when viewed with Safari 12 to remove the Safari connector as an option.

Looking into this a bit more, even if we were able to distribute a Safari App Extension, which we can't currently, it would likely be much more limited: no dynamic save icon, I think no RIS/BibTeX interception or proxy redirection (which is already more limited in Safari), more limited interaction between the connector and Zotero for things like updating the collection chooser, and probably various other things going forward.

(Zotero aside, this change will also mean the end of any Safari extension not linked to an app, unless Apple makes it possible to distribute these new-style extensions another way.)

Yeah, so the guidelines say “should include some functionality, such as help screens and settings interfaces where possible”, which seems somewhat contradictory (is a help screen "functionality"?) but ultimately does seem to allow fairly empty container apps.

In our case, I'm pretty sure we'd need to reimplement at least the entire preferences system in the native app, and possibly more, just to end up with a much more limited extension than in Chrome and Firefox. I don't really see us doing that. I think it's much more likely that we'll just update the bookmarklet, since that would allow you to do most of what you'd be able to do with the new Safari extension anyway.

Does this mean that if I do not upgrade to 10.14 or Safari 12 (is Safari 12 automatically included in 10.14?), I should continue to use Zotero as usual?
Thank you.

@nschct: Once 10.14 and Safari 12 are released this fall, you'll want to upgrade at least to Safari 12. Apple doesn't put out security updates for previous Safari versions, and using a browser that's not receiving security updates is incredibly dangerous. So you won't be able to use the Zotero Connector in Safari after that point. We'll also stop updating the Safari connector then, since no one should be using a compatible version of Safari any longer.

You can use the Zotero bookmarklet (which we'll be improving) in Safari 12 or, as DWL says, switch to Firefox or Chrome for a better experience (which is already the case, because the current Safari extension framework is already more limited).

Holy cow, I was about to upgrade to Safari 12, until I decided to dig up some online reviews. Thanks god I did that.

Is it still possible to download the old extension for earlier versions of Safari please?

Thank you – sorry, was looking at it via an updated Safari rather than the non-updated one!

Safari 12 was installed automatically by my university this morning. Safari connector stopped working this morning. Do we have an idea when this will be resolved?

bwiernik: I don't think there will be any security updates for Safari 11. Safari 12 IS the security update for Safari 11, that's one of the reasons it comes to old versions of macOS (Sierra and High Sierra).

Sooner or later everyone must move on. Either switch to another browser if you think the changes in Safari are unacceptable; use the bookmarklet; or use a secondary browser like Firefox for the Zotero extension. That's actually my workflow. I use Safari for my day-to-day browsing but also have Firefox for functions and extensions that Safari does not have. And it could not be easier: make sure you have the Develop menu enabled in Settings/Advanced and every time you need to open a page in another browser, just go to the menu bar, Develop/Open Page With. Not ideal, but no big deal either.

I found a bypassing method.
I don't have a Mac computer with me now.
Could somebody try?

French: https://hackernoon.com/how-to-bypass-safari-12-unsafe-extension-warning-c96349121e59

English: https://sixcolors.com/post/2018/09/give-new-life-to-old-extensions-in-safari-12/

[Edit: English version added — D.S]

I note that AdBlock, a much more intrusive and complex extension has transitioned to the new model. So it seems that this isn't actually technically that complex (as they also support multiple platforms). I think not addressing Safari on MacOS in the academic community is somewhat short sighted. Perhaps, like AdBlock, the existing codebase can be divided into the Safari internal extension elements and the configuration can be placed into the Zotero MacOS desktop app?

@ms08th in reply to: "Why does Apple do so?" While I can understand your frustration, I feel like this line of discussion is off-topic here. I would also suggest your energy is better directed towards Apple. Please register your feedback directly with Apple, here: https://www.apple.com/feedback/

As for this thread, I would request we focus on what Zotero can do, in terms of solution(s) and/or workaround(s).