James Huff - "The core WordPress developers are already doing their best to keep things backwards-compatible, they provide complete transparency during development with the ability to test a month before the release, and WordPress has a huge and helpful support community for any developer (and user) who has run into trouble."

Sarah Gooding – "Wow, I don’t know who you have working for you but this is very unusual from my experience. You can always prepare for updates by staging them on a development site while they’re still in beta."

Justin - "If something breaks on update, more times than not it wouldn’t be a backwards-compatible issue when it comes to WordPress. It’s probably more of a problem of poor code. That comes down to education for developers, which I think WP is making great strides with on a number of fronts."

Peter Knight - "Plugins will fall into disuse if their developers stop working on it. This has absolutely zero to do with how well WP scores on backwards compatibility. Third party code just needs to be maintained..."

Jason "WordPress" Kiles - "Gotta agree with the above comments, there expectations of back-testing for thousands and thousands of free plug-ins, many of which have been all but abandoned by the original developers, can’t be dropped at the feet of one small group."

Wow indeed! James, et al. Do you guys not even hear yourselves? We are having a MAJOR disconnect over a definition of terms. It seems that all of you have confused 'backward compatibility' with 'developmental transparency'. It's not the same thing. Never has been. Not even close. In case you have forgotten:
(http://en.wikipedia.org/wiki/Backward_compatibility) "In telecommunications and computing, a product or technology is backward or downward compatible if it can work with input generated by an older product or technology.[1] If products designed for the new standard can receive, read, view or play older standards or formats, then the product is said to be backward-compatible; examples of such a standard include data formats and communication protocols. Modifications to a system that do not allow backward compatibility are sometimes called "breaking changes."

Sarah - When you say, "I don’t know who you have working for ..."; Is that the standard that you expect for a WP user?; that they are employed as a PHP programmer? I find that quite telling and indicative of the bias that I have been trying to illustrate.

Justin - You said, "...education for developers..." So what do you think the difference is between users and developers? You have made my point for me.

Peter Knight - "Plugins will fall into disuse if their developers stop working on it." Again, thanks for making my point about 'backward compatibility'.

Jason "WordPress" Kiles - "...many of which have been all but abandoned by the original developers, can’t be dropped at the feet of one small group." Developers again. OK. You do realize that my original comments was about 'backward compatibility' and 'users' - not developers. And yes, this falls squarely in the purview of the WP core file developers.

Like I said, WP is the king of content management platforms. It's a great system. But with WP updates, things "break". For all you developers out there, no big deal. You have a 'window' in which to see where your code will break and the opportunity to fix it.

It seems that most of you guys are intimately familiar with WP. Many of you are familiar with HTML5, CS3, PHP, JS, etc., right? Well I know a little about standards and compatibility (related field). The WP 'team' may be working on backward compatibility, but I've got a bulletin for you. They aren't there yet. Again, not even close.

QUESTION: If WP is backward compatible, why provide the opportunity to test theme and plugin code - and the opportunity to fix it with every update? Why do themes and plugins need to be 'constantly maintained'?

ANSWER: If WP is backward compatible, you don't need to test and they don't have to be maintained at every update.

Your perspective is skewed. The simple truth is that the normal DIY 'user' that installs WP through their web host will not be familiar with PHP or anything else related to 'development'. Should they find a plugin or theme upon which they build their vision, many will end up being disappointed. Something will break. There are even odds that they will not find a suitable replacement. Their WP 'experience' will suffer as a result. That is the point I was trying to make. Is that really so hard to understand?