As we all know, Apple decided in its wisdom to remove the OS X 10.10 SDK from Xcode as of version 7 (this happened in one of the betas). At the time, I filed a bug (rdar://22378220), to which I got the response:Some considerations:1) setting the deployment target lets you target older OSes2) for iOS SDK, Xcode only ever supported one SDK3) Swift offers a great new availability checking syntaxOn observing that the deployment target setting is all well and good, but that I was getting errors about libkmod, the bug was closed with the comment:We're not pulling back the 10.10 SDK into Xcode 7. Yes, there will be some adjustment for developers, but we think this is the right path forward.We're addressing the libkmod issue with our internal Bug ID 22720041.We are now closing this bug report.Well, we’re now up to Xcode 7.2 and there’s still no fix for the libkmod problem. Moreover, when I filed another bug report about the fact that KEXTs built against the 10.11 SDK don’t