Supporting C++11 will allow nice additions, but it won't replace many things. After this change, I think you'll still be able to write a program that uses mostly C++98, if you want to.
Regarding backward compatibility and maintenance of older versions, it's true that we'll move forward and focus on improving the latest versions, but I think it would be wise to spend some time back-porting bug fixes to the latest revision of the previous major version (i.e. 2.x after 3.0 is out). If we want SFML to be used in the real world, and not only for short-term small projects, we have to care a minimum about backward compatibility, and not abandon users who would not stick to the latest version. So where should the limit be? I don't know, but this should definitely be discussed.
If it can be done easily/nicely then sure. So yeah we'll have to discuss this in detail.
..and people who don't use C++11 will have to go and learn a whole new set of skills. A good thing, but you're only going to get questions from people who don't know it inside out. Allow it, but don't enforce it.
The discussion around C++11 is only whether the compiler has to support it or not. As for using SFML's public API you most likely won't have to know C++11, but if you do, you might be able to write more performant and nicer code.
Indeed. But there are real people who want to make games or whatever using SFML, who maybe don't have much money, and so buying new hardware also isn't an option.
Yes, unfortunately we can't limit innovation to support someone's old hardware. I mean we're working for free and try to listen as much to the community as possible, so if there's anything specific that wouldn't work for someone, we'll try to find a satisfying solution for both sides.
If you think that's not enough, then I might point you to the commercial sector, where everything is done based on profit. Have you seen AMD, Nvidia or Intel releasing new drivers for dead old hardware?
I know, but also remember that there are companies and individuals who donate hundreds, if not thousands of Euros every year to allow the purchase of hardware, etc, which also allows the project to continue...
Again, not really a concern regarding SFML's development. If we would calculate all the time Laurent and all other developers of SFML spent on developing and supporting this project and multiply it with a "normal" senior developer salary, the cost on hardware would rather quickly shrink in comparison.
Just out of curiosity, if you're allowed/willing to tell us. Which company do you work for? In what kind of kiosks does SFML get used?
I mean in the end, one could always discuss/think about something like a partnership - libraries that are backed by companies often gain in popularity and over all code quality. Not that this is in any way my decision to make, just thought I throw it out there.