Meridian 565 vs. 561 Differences?

Can the 565 be upgraded to 7.1 capability? What does the 561 offer that you can not get on the 565 or vice versa. Do both or either have analog by pass? I am trying to decide which to buy. Thank you.
The 565 has 1 digital coax, 1 digital optical and one analog input. If you have a minimalist system it can work as a stand alone uniit. If you have more sources, then you also need a 562V. You plug all your sources into this box, then 1 digital to the 565 and 1 analog. The 562V switches and routs all of your sources to the 565 for processing. The 565 was upgradeable all the way to Dolby Digital and dts 7.1 I believe. Set-up programming is all done through a difficult menu system from the front panel switches. The 565 is a great unit and sounds better than the 561. The 561 was the first one box solution featuring several inputs. It also has computer based set-up interface that is much easier to use. I am not sure how far the upgrade path this unit will go since it is still a current production model. The 565 will not be upgradable any further. The 568 is the replacement for the 565 with more inputs and the computer interface. Let me know if you need any more details.
The 561 is strictly digital, no analog bypass. It does have a wealth of analog inputs, however the signal is coverted to digital. There is one Toslink, and at least two digital rca inputs. The 561 uses 20 bit dacs as opposed to the 565 which is upgradeable to 24 bit dacs. The 561 supports 5.1 only when using analog outputs. It can support 6.1 and 7.1 if the L/R mains are Meridian digital speakers. The firmware in the 561 is upgradeable by the user and can be downloaded from Meridian's website. Version 1.75 contains all of the latest formats including EX, EZ (Meridian format), and PL II. There have been no hardware upgrades that I'm aware of for the 561. The 561 can also support a Meridian proprietary 'firewire' type connection with Meridian DVD players for a superior transfer of digital signals, including DVD-A. I apologoze for the simple explanation, more information on this proprietary connection is available on Meridian's website.

I don't believe the difference in sound between the 561 and 565 is that great. I've owned the 508.24 player, and it did sound better, but not by a large margin. I think the superior and more intuitive setup interface of the 561 would outweigh any marginal benefits the 565 would have in sound quality. The 561 is an all in one package with many inputs and video switching.
The 565 is upgradeable to the early version of the 568. The 565 last upsate version is the V6.2A which is autodetects video DTS and so on. I also believe the 565 sounds better than the 561 enough to say its not worth the price increase. Also 24 bit DACs then the 561 20 bit DACs for the 561 another difference. Also for the price that a good used 565 can be purchased, you can also pick up a 562v or v2 which gives you a multitude of inputs and outputs for the same price as most 561's. But at the same time, the updates i beleive as of now are done for the 565. My current belief with how slow video DVD's are progressing, this 565 would be current for quite sometime yet. ALot of the dvds today are still 5.1 only and although becoming more common, the DTS discs aren't super common yet let alone the other version of EX or ES and so on. As for music, i think the 565 is the winner between these two. HOpe this helps.