A beta release of OS X Mavericks 10.9.5 held a surprise for Mac developers thanks to changes in the Gatekeeper app security feature that could leave end users scratching their heads wondering why apps no longer launch. Apple is changing how apps will be digitally signed to verify they aren't malware, and developers will need to recompile their code to comply with the Gatekeeper update.
Apple drops surprise Gatekeeper update on Mac developers
Gatekeeper is a feature in OS X that helps protect Mac users from malicious apps. Developers are assigned their own unique key they use to "sign" their apps, and those digital signatures are verified by Gatekeeper. Apps with proper signatures are allowed to run, but unsigned apps trigger a warning dialog when launched.
Mac users who update to Mavericks 10.9.5 when it is released -- most likely some time this summer -- won't notice the change if the apps they use have already been updated to be complaint with Gatekeeper's changes. Apps that haven't been updated will still run, but users will have to take an extra step to make that happen by Control- or Right-clicking the app and choosing "Open" when they launch it.
The warning dialog Mavericks 10.9.5 users will see when trying to launch unsigned apps or apps without a verifiable signature will likely lead to unhappy customers who vent their frustration on developers. For developers, this is yet another task they have to add to their plate even as they work on getting their apps ready for this fall's OS X Yosemite release.
Mac users who don't install the 10.9.5 update shouldn't see any changes because they'll be running the older version of Gatekeeper. According to Apple, the new version 2 signatures will be recognized by older versions of Gatekeeper. Users running Mavericks 10.9.5, however, will need apps with the version 2 signatures to avoid warnings.
For developers, that means they need to be running OS S Mavericks or newer for their coding environment because Gatekeeper's new signatures aren't available in older versions of the Mac operating system. While most developers are running the latest version of the Mac OS, there are some who haven't made the move to Mavericks yet. For those, it may be time to make that move, especially since the new Gatekeeper signatures will be part of OS X Yosemite, too.