Which is the earliest Apple TV that can mirror an iPad?

So, I need to mirror an iPad Air 2 (not just spare apps, the whole screen and audio) wirelessly to a projector, and I was thinking of buying an Apple TV. However, since the current version is so expensive, I thought of buying an older one (say, TV 3rd Gen version A1427, A1469 or 2nd Gen). Somehow, I couldn't find this in the Apple help (I guess... because they update it to the latest version, sometimes "hiding" previous ones).

Which is the earliest version that can (decently) screen mirror an iPad?

The Apple TV 2 is the earliest Apple TV that supports AirPlay Mirroring, being the earliest Apple TV capable of installing Software Update 4.4, which added the feature.

AirPlay Mirroring: Wirelessly stream what's on your iPhone 4S or iPad 2 screen to your HDTV.

^{https://support.apple.com/kb/HT202157}