Adoption of Apple's new iOS 9 was slightly ahead of the pace of last year's iOS 8 as the upgrade neared the 48-hour mark, but, like its immediate predecessor, was far behind that of 2013's iOS, according to data from an analytics firm.
That was lower than the 15.6% accumulated by iOS 8 last year at the same post-release point, and much lower than the 29.9% that iOS 7 collected in 2013 within 24 hours.
However, at the 44-hour mark, iOS 9's adoption surpassed that of iOS 8, reaching 20.1% compared to the 19.4% of its forerunner. But both were blown out of the water by iOS 7, which accounted for a whopping 43.3% after 44 hours of availability.
The better performance of iOS 9 later in its cycle may have been due to troubles some users encountered in grabbing the upgrade immediately after it was released by Apple. For at least the first hour of availability on Wednesday morning, users -- including some Computerworld staffers -- were unable to access the download.
iOS 9's -- and iOS 8's before it -- failure to match the rapid adoption tempo of iOS 7 may be simply because of the intense interest in iOS 7, which was the first major visual overhaul of the iPhone's operating system since the smartphone's 2007 debut. The larger numbers of iOS devices in use compared to 2013 could also be contributing to the slower adoption: As a user base increases in size, it's inherently more difficult to reach the same percentage of change. Microsoft's Windows suffers from a similar problem when compared to the much smaller user base of Apple's OS X, for example.
But even a slower upgrade cadence for iOS has rivals green with envy. iOS 8 was on 92% of all iPhones, iPads and iPod Touches just prior to iOS 9's launch two days ago, according to Mixpanel's data. Apple continued to peg iOS 8 at 87% on its developer website.
Last year's Android release, dubbed "Lollipop," now accounts for 21% of all Android editions, or less than one-fourth of iOS 8's share. Lollipop debuted in November 2014.
Assuming iOS 9 doesn't harbor show-stopping bugs -- as did 2014's iOS 8 -- it will be an uptake improvement over its predecessor, predicted Crittercism, a vendor that markets a platform that tracks crash data to app makers. Like Mixpanel, Crittercism can detect the iOS edition being run by a device.
Using past data, Crittercism earlier this week predicted that iOS 9 would be adopted at a faster pace than was iOS 8, reaching 20% by Day 4, or early Sunday. (In actuality, iOS 9 cracked the 20% bar early Friday.) The most important difference between the two editions that led it to its conclusion was the smaller amount of free storage space required to install iOS 9.
While iOS 8 demanded as much as 5GB of open storage space to install the upgrade after downloading it over the air -- forcing those with small storage-sized devices like the 16GB iPhone to turn to the awkward iTunes-based approach -- Apple has promised that iOS 9 requires less than 2GB of free space.
iOS 9 can be downloaded over the air from iPhones, iPads, and iPod Touches, or through iTunes. From an iPhone, for instance, users must tap the "Settings" icon, then the "General" button on the resulting screen. Tapping "Software Update" will kick off the process.