There are two dangers that may arise if people try to feed 3D through v1.3 receivers and processors. The first is bandwidth: even though v1.3 is spec'd to handle enough bandwidth for 3D, that doesn't mean products' internal architecture was built for it when all they had to worry about was 2D 1080p/60. There's no way to readily identify if this could be a problem or not with a v1.3 product. The other is video processing. Some units (like the Onkyo 885 and 886) will automatically bypass video processing when fed a 1080p/24 signal. Other units can't do that, and 1080p/24 comes out 1080p/60. Can the former units be "trained" to bypass a 1080p 3D signal? Can units that don't know to bypass 1080p/24 be "trained" to?

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If the internal bandwidth doesn't exist to handle two 1080p signals concurrently, a firmware update won't fix it. Likewise, video processing that wasn't meant to pass such signals may not be able to be "fixed" after the fact to support it. There are already products on the market that can't pass 1080p/24 and even a few that can't pass 1080p without interlacing to 1080i and re-deinterlacing to 1080p. Those are almost guaranteed to choke on a 1080p 3D signal, and identifying such units is a difficult and tedious process (the ones I'm thinking of are all v1.3). Also consider how quickly the 3D standards have come together - folks can't have designed with this standard in mind because the standard was still a complete mystery. There's no telling what the 997 would have supported regarding 3D video signals. The fact that the 998 will have v1.4, on the other hand, means that it isn't an issue either way.