Several research and analytics firms have reported that iOS 8 adoption has reached 30% following the first weekend of iPhone 6 and iPhone 6 Plus sales, based on in-app analytics reported by Fiksu, Mixpanel, Appsee, and Chitika. While this number is up from the estimated 15% adoption following the initial iOS 8 public release last week, it still falls short of the almost 50% of users that had updated to iOS 7 by this time last year. The higher adoption…