Licensing an SDK has unique challenges that often do not need to be considered when writing a typical application. Since our SDK is integrated into thousands of apps, people expect our API to be consistent, and ideally it shouldn't ever change (unless someone runs into a limitation). We're taking great care to evolve our API in a meaningful way, and often the design is forward-thinking, so future extensions are easier.
Presented at Cocoaheads Portugal, Feb 4 2019.