You mean, "IOS 5 is dead for services that use mixpanel". These "trends" in no way tell the story of the wider internet or other device usage. Consider the "mobile v desktop" report [1], supposedly mobile usage fell off over the first few weeks of March and then came back. Rubbish, what it says is that mixpanel has a changing client base that skew their stats.
[1] https://mixpanel.com/trends/#report/desktop_vs_mobile