There isn't one. After 30 years of trying to distance themselves from Redmond, Apple has subscribed to the Microsoft School of Counting.

This happened with the 3GS (which should have been 4), and has continued since then.

The iPhone 4 was actually the only iPhone with a number which coincided with the generation; before it, there was 2G, then 3G, then 3GS, then 4. If anything, the 3GS should’ve been called the iPhone 3, but they’ve been pretty clear from the start that the name doesn’t really reflect a simple incrementing version number.

The also went form the original to 3G. 3GS was actually #3.

Failed like Windows 9.

I wonder if the plan is to keep refreshing the iPhone X into the future, like all other X/10 versions seem to do.

iPhone X One X

Looks like a Windows 8.1 -> 10 naming change, it must be in style to be inconsistent :)

I had read part of the decision was based on minimizing confusion with 95/98 versions of Windows. Who knows?

Seven ate nine

10 years. C'mon people...

Base-8 encoding: ... 6, 7, 8, 10, 11, ...

:-)

That would be base-9 though

funny, but 8=10 so technically base 9

What about Debian 9?