While the iPhone X and iPhone XS have identical overall dimensions, a new report suggests that iPhone X cases may have a slightly imperfect fit on the iPhone XS due to very slight changes to the camera bump dimensions.
No, the camera bump is not any thicker, as Daring Fireball's John Gruber confirmed in his iPhones XS review on Wednesday. However, eagle-eyed Japanese blog Mac Otakara has discovered that the camera bump is ever so slightly longer and wider on the iPhone XS than the one on the iPhone X.
Head over to the translated report for specific numbers, but the gist is that the iPhone XS camera bump is up to a millimeter or two longer and wider than the one on the iPhone X, potentially affecting case compatibility.
We expect that most iPhone X cases will more or less fit the iPhone XS without issue, but Mac Otakara provided a photo of an iPhone X in Apple's new iPhone XS Leather Case, and you can see that it isn't quite a perfect fit. The camera bump should be flush with the opening in the case, and it's off just a bit.
In other words, the camera cutout on the iPhone XS Leather Case is a bit larger, to accomodate for the new iPhone XS camera bump dimensions. In reverse, the camera cutout on an iPhone X case may be a bit too small for the iPhone XS.
All in all, treat this as a warning that some iPhone X cases, especially ones with a very tight fit around the camera bump, might have an imperfect fit on the iPhone XS. It's not really a big deal, but something to keep in mind.