Two days after Apple released iOS 11, almost 15 percent of all Apple devices have been upgraded to its latest software.

The stat comes from product analytics company Mixpanel. As of 11 a.m. EST on Sept. 21, the company reports that about 14.5 percent of Apple devices have been upgraded to iOS 11, with 78 percent of devices still running iOS 10.

It looks like iOS 11 adoption is about as fast, if slightly lagging, as how quickly iOS 10 spread last year. According to Mixpanel, after iOS 10 had been available for a day in 2016, about 15 percent of users had already upgraded to the latest Apple software.

However, two days after iOS 10 had been released, just over 20 percent of devices had been upgraded. We'll see if iOS 11 matches last year's upgrade adoption when Mixpanel updates its data.

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As with anything Apple releases, iOS 11 has been subject to a massive amount of critique, though much of it has been positive. Mashable's review underscored that iOS 11 is supported on older iPhone models going back to the iPhone 5, provides "extraordinary" features on the iPad (such as drag and drop), and cool features on the iPhone, including turning Live Photos to GIFs.