Apple’s latest mobile operating system, iOS 9, launched to all Apple mobile device users today.

The rate at which people adopt the new OS might say a lot about the new features and functions included.

Mixpanel, which makes a predictive analytics product that developers pull into their apps via an SDK, is tracking the uptake of the new OS.
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Click on the chart above to see the real-time adoption tracking. 

“We’re drawing data from people using applications that Mixpanel’s SDK is in,” said Mixpanel CEO Suhail Doshi in an email to VentureBeat.

“We work some of the biggest companies in the world (Uber, Spotify, Whisper, etc.) and tens of thousands of other apps to derive highly statistically confident data. We’ve done this report over the last 3 years with both iOS and Android and it’s been highly accurate,” Doshi said.

As you can see on the chart, the bottom line of red dots representing iOS 9 is just starting to take off. And the number of iOS 8 users is beginning to dip.