It's not only outdated (last updated early 2005) but it's been deprecated by other free offerings- particularly codeblocks. Most of the developers who worked on Dev/C++, as guss stated, are now working on code::blocks- it's unlikely Dev/C++ will be enhanced in the future. This isn't even counting the issues I noted (such as using a User interface dialog from over 20 years ago).
Why should it matter?
Because people who use compilers usually want their programs to work with recent configurations. An analogous statement could be to ask "why it matters" wether your windows SDK is for windows 95 or windows 7. Of course considering I'm arguing with somebody who still thinks FORTRAN is the bees knees clearly I'm wasting my breath.
I have tools I got over ten years ago and they still work for simple tasks.
Compiling the code to a project-organized application is anything but a simple task. The fact is dev/C++ is free. So is Code::Blocks. code::Blocks is better, more compatible, and is still an active project.