Lieb recently shared these figures on Q&A service Quora where they were soon spotted by our own Marshall Kirkpatrick. The answer Lieb posted is a standout example of why the tech community is currently hyping the Q&A startup Quora to such a great extent, even proclaiming it to be the next Twitter, in some cases.

But back to the data at hand.

Lieb said that Bump's user base is large enough to be a good statistical sample. However, he doesn't state how large. But we do know that as of August 2010, the Bump app had been downloaded 15 million times. In addition, we asked Lieb this morning where Bump stands as of today. The app has now had more than 25 million downloads across iOS and Android, he told us. So yes, we're buying it that their sample is large enough to be of interest here.

For the data below, Lieb says that the sample comes from all Bump users between January 7 and January 10, 2011. This data includes all iOS devices, though, not just the iPhone.

By major revision, the statistics are as follows:

• 4.X: 89.73 %
• 3.X: 10.25 %
• 2.X: 0.02 %

And by individual minor revisions, the stats are (ranked by percentage):

• 4.2.1: 52.89 %
• 4.1: 27.50 %
• 3.1.3: 6.43 %
• 4.0.2: 3.36 %
• 4.0.1: 2.95 %
• 4.0: 2.94 %
• 3.1.2: 2.52 %
• 3.2.2: 0.49 %
• 3.0: 0.22 %
• 3.1: 0.21 %
• 3.0.1: 0.10 %
• 3.2: 0.10 %
• 3.1.1: 0.10 %
• 4.2: 0.09 %
• 3.2.1: 0.07 %
• 2.2.1: 0.02 %
• 2.2: 0.00 %

In addition, Ian Peters-Campbell, an engineer at Loopt, makers of a location-based iPhone application, responded to the question saying that Loopt's stats were very similar to the above, but with even a little more of its users on iOS 4. Lieb said that made sense since Loopt probably had more iPhone users (vs. iPod Touch users) than Bump did.

What this goes to show is that Apple's mobile operating system isn't too badly fragmented, especially when compared with its competitor, Android. On Android, as of today, only 0.4% of Android devices are on the most recent version - version 2.3 aka "Gingerbread." Of course, Gingerbread is brand-new, so even looking back pre-launch to December 2010, we found that only 43.4% ran Android 2.2 (Froyo), then the most recent version.

Image credit: TiPb