“Today is a big day for Android… 500 million devices activated globally, and over 1.3 million added every single day,” said Hugo Bara, Android’s director of product management, in a Google+ post. It’s not clear how many devices are replacing older ones, though.

Barra said in June at the Google I/O show that 400 million Android devices had been activated and that the rate was 1 million per day. He also noted that the Jelly Bean statue, which commemorates Android 4.1, is back on the Google sculpture gallery that shows off the various dessert-themed versions of the mobile operating system. The statue had to go back into the shop for repairs shortly after its debut.

Android 4.1 ships with the Galaxy Nexus, a smartphone made by Samsung, and the Nexus 7, a tablet made by Asus, but not on much else yet.

Indeed, the transition to Android 4.0 aka Ice Cream Sandwich is still grinding along slowly, with the earlier Android 2.3 aka Gingerbread still claiming 57 percent share of usage. Gingerbread is looking more and more like Windows XP: an operating system whose wide use means developers will have to support old technology for a long time. Jelly Bean has 20.9 percent of usage, now finally increasing steadily after months of little movement following its 2011 debut. Jelly Bean is at 1.2 percent, according to Google’s measurements.