title: Module compiled with Swift 5.1 cannot be imported by the Swift 5.1.2 compiler
body: <p>I have a framework (in this instance it's RxSwift) which I've compiled using Xcode 11.0 into the traditional <code>RxSwift.framework</code> style package</p>
  
  <p>This imported fine into Xcode 11.0 and also 11.1 never had any problems with it</p>
  
  <p>Today, upon Apple's release of Xcode 11.2, I upgraded, and I am presented with the error:</p>
  
  <p><strong>Module compiled with Swift 5.1 cannot be imported by the Swift 5.1.2 compiler</strong></p>
  
  <p>I'm used to swift compiler mismatches, and I'm aware I can just recompile RxSwift using Xcode 11.2 and carry on, but the headline feature of Swift 5.1 was <strong>module stability</strong>.</p>
  
  <p>I was under the impression that now that we have module stability, frameworks won't need to keep getting recompiled with every new Xcode release, yet this is clearly not the case.</p>
  
  <p>If anyone can explain what is going on here I would much appreciate it. Is Xcode 11.2 exhibiting a bug? or did I somehow need to tell it I wanted module stability when I originally compiled with Xcode 11.0?</p>