If you were watching the live stream of the Apple TV launch, the eagle eyed-amongst you may have noticed something a little different about the the new model. And no, it's not the fact the new Apple TV is a touch taller than its predecessor - 10mm to be precise.
The back shot of the new Apple TV box showed that ethernet and HDMI sockets were both present and correct, but there was one socket missing: the optical output.
Okay, so losing the optical output isn't the end of the world, but it will certainly be an annoyance for some and it's food for thought for anyone looking to stream their Apple Music library straight into a desktop DAC, with a view to getting the best sound quality possible.
This makes the 4th-gen Apple TV only compatible with devices with an HDMI input, i.e. TVs, AV receivers, soundbars, soundbases and some standalone DACs.
You aren't exactly spoilt for choice when it comes to DACs with HDMI inputs. We've reviewed a couple over the past two or three years such as the Lindy LDAC Pro and NAD M51, but optical is still by far the most common connection used by DACs.
There was also no sign of support for 4K video, despite the fact the new iPhone 6S and 6S Plus can shoot for 4K video for the first time.
While a special Netflix app for the new Apple TV box was shown during the Apple launch, clearly this won't be the version seen on some of the latest 4K TVs, which comes complete with a small but growing library of 4K Ultra HD content.
So if you do have a 4K TV and fancy the new Apple TV box, you'd have to switch between the box and your TV's Netflix app to see that streaming 4K content.
But it isn't all bad news. Apple has included support for 7.1 audio decoding, only 5.1 Dolby Digital pass through was available on the previous model. Quite how much compatible 7.1 content is going to be available remains to be seen...
MORE: Apple TV hands-on review