Incompatible as a stereo pair? If they improve audio quality, then pairing different quality speakers wouldn't produce a perfectly symmetrical sound which would make it much more complicated to control and probably produce non-ideal results regardless.Knowing Apple they’ll make them incompatible with version 1.
I’ve got several and they are fine. If the audio quality is improved I’ll consider upgrading.
Probably the only way they'll be compatible is if Apple doesn't improve the audio quality.