As far as we're aware, there is no Magic Mouse 3 release date. In fact, Magic Mouse 2 is a catch all term that describes the Magic Mouse since its 2015 release, when it proceeded the Magic Mouse 1 (which released in 2009). That's not to say the Magic Mouse has stayed the same since 2015. Its port has since changed to a USB-C/Lightning, and there are various colour options that are new. But if you're talking about the Apple mouse post-2015, you're talking about the Magic Mouse 2. To distinguish the iterations, it's best to specify the year of release.