We did skip the following numbers:
1 and 9.
The original iPhone in 2007 was unofficially dubbed as iPhone 2G
In 2017 with iPhone 10th anniversary, Apple jumped the queue with iPhone X whilst still having an iPhone 8, then the year after that iPhone XS to skip a number then we resumed to the iPhone 11 Pro and iPhone 11 in 2019 to introduce a pro and regular variant of iPhone.
This is actually going to break a **** ton of apps, knowing how app developers doing their versioning checks. It's already bad when an app breaks when a new OS releases and the developer didn't purposefully add in the latest OS identifiers.