need some tweaking to ease compatibility between old upgraded set top boxes delivering 3DTV, Blu-ray 3D, receivers and displays was already established and today the full information has been released to all HDMI Adopters. Firmly implemented are the mandatory formats devices will need to interpret with displays required to support all mandatory formats, repeaters able to pass through all of them, and sources must support at least one. That certainly doesn't stop older HDMI 1.3 labeled equipment from delivering a Full HD 3D experience, as long as they're able to upgrade to compatible signaling.
As HDGuru explains, the main potential hangup is in the audio receiver, as older ones without 3D passthrough capability may not be able to interpret 3D signals, and can't be upgraded to interpret it requiring a workaround like Panasonic's upcoming dual HDMI packing Blu-ray player. Whether it's "frame packing" (sequential) in 1080p/24Hz for movies or 720p/60Hz for games, and either side-by-side horizontal at 1080i/60Hz or top-bottom compressed 720p/60Hz and 1080p/24Hz for TV the new updates to the spec just ensure everyone is speaking the same language going forward. We haven't heard of any looming compatibility issues for 3DTV devices but until it gets in someone's home and the cables are plugged in we're sure some will still have doubts.