iPhone X and Xs may look exactly the same to the human eye, but the camera’s notch on the back has slightly different dimensions.
As the Japanese Appleblog macotakara found out, the camera dimensions are not exactly the same. The dimensions differ in the millimeter range.
Consequence: It is possible that sleeves do not fit exactly. With cases made of soft material this may be ok, with hard plastic cases it may happen that they just don’t fit. This is true if you want to use “old” iPhone X cases with the Xs. Conversely, it should be no problem, since the recess in the Xs is slightly larger.
However, as many sleeves are currently offered for the X and Xs, only one thing helps: try it out.
