> That is, half of Android devices were on an OS that hadn’t seen an update in at least 2 years.
This seems quite wrong, older Android versions do receive some security maintenance releases from google. It's of course up to the device vendor if a particular model gets it though.
This is info is a bit hard to find but it seems like KitKat was supported until October 2017, Lollipop until March 2018 and Marshmallow until August 2018. (taken from wikipedia and here: https://www.quora.com/Will-the-Android-5-Lollipop-still-exis...)
So you could be running a phone with KitKat, which was released in 2013 but still got the last update 1.5 years ago.
This seems quite wrong, older Android versions do receive some security maintenance releases from google. It's of course up to the device vendor if a particular model gets it though. This is info is a bit hard to find but it seems like KitKat was supported until October 2017, Lollipop until March 2018 and Marshmallow until August 2018. (taken from wikipedia and here: https://www.quora.com/Will-the-Android-5-Lollipop-still-exis...)
So you could be running a phone with KitKat, which was released in 2013 but still got the last update 1.5 years ago.