General
iOS + Android
- mixpanel.com/trends – Various graphs and reports on OS version and device adoption
- nodesagency.com/os – OS version distribution in their customer’s apps (mainly UK, >5 millions sessions per month)
iOS
- developer.apple.com/support/app-store/ – Official data from Apple: Simple 3 part cake diagram that shows last two versions and rest of iOS traffic on App Store
- david-smith.org/iosversionstats/ – Detailed iOS version and device stats from a very popular free app
- willhains.com/iOS-version-history – iOS version vs. how long it was the current version (same for beta versions!)
Android
- developer.android.com/about/dashboards/index.html – Official data from Google on Android version, Screen Sizes and Densities based on visits of Google Play Store
- fossbytes.com/most-popular-android-versions-always-updated/ – Monthly writeups of official data from Google
Market Research
- deviceatlas.com/mobile-reports
- www.gartner.com/newsroom/archive/ (Search for „mobile“ or „smartphone“)
- www.visionmobile.com/library
Browser market share
Release and Version History
Wikipedia has excellently sourced and edited version history articles for both platforms: