For anyone out there that picked up a lot of cases that they really liked for their iPhone 5s, and plan on upgrading to the similarly-sized iPhone SE, the good news is those cases will work with the new 4-inch phone. That’s not really the case with the new 9.7-inch iPad Pro, though, despite sharing similarities to the iPad Air 2.

Apple managed to keep the same dimensions for the new iPad Pro as they launched with in the iPad Air 2. Meaning, the new tablet measures in at 9.4 inches by 6.6 inches by 0.24 inches. However, just because the similarities in dimensions are there, it turns out that a few subtle changes in the new iPad Pro make it hard for accessories, like the iPad Air 2’s Smart Cover, to work with the newest 9.7-inch tablet from Apple.

Apple, for its part, did launch new Smart Covers for the new iPad Pro, designed specifically to accommodate the newest tablet’s design. Specifically, these new Smart Covers accommodate the Smart Connector on the new iPad Pro, to which the older covers simply can’t do, for obvious reasons. As noted initially by Macworld, the inclusion of the Smart Connector means the magnetic alignment for the Smart Cover is different.

So Apple says it is “not recommended” to use a Smart Cover that was initially designed for the iPad Air/Air 2 on the new iPad Pro. The same can be said for the iPad Air 2’s Smart Case, which isn’t designed to match the new iPad Pro’s four speakers, Smart Connector, or even the rear flash for the new tablet’s 12-megapixel camera.

A bit of a bummer, probably, for owners of the iPad Air/Air 2 that plan on upgrading, but considering the changes Apple made to the design, makes sense. Do you plan on picking up a 9.7-inch iPad Pro?