[oneJob]

Applications are rarely released in explicit versions (from the user side, publicity wise, sure there is a version number in the version control process, but what percentage of Gmail users do you think know what version they are using). If Apple has an application that is successful then they will continue to iterate that code base. If Apple truly is of the opinion that Swift is the language of the future, one would expect them to utilize it going forward. In order to utilize it going forward they'd need to rewrite some of the code base when they fix bugs and change functionality or aesthetics. The remaining code base can be left alone so long as they are confident they can get the resource to work with it if needed in the future. So really, what Apple is saying is, it's still easy enough to get someone to work on Objective-C should an issue arise. When that talent pool dwindles, at that point Apple will need to look at the cost/benefit of rewriting large code bases again. That is all assuming Apple has commited to moving to Swift and away from Objective-C, which I doubt is the state of affairs just yet.