Last release was 2014. I remember liking dia, but I forget...it either crashed or didnt have all the aws icons I wanted when I used it last 5 years ago, and there hasn't been a release since.
That person’s entire criticism of Dia is “it’s old”. That’s it; not even “the program, when I run it, looks old”! They merely criticize the web page for having old screenshots and support for old operating systems on it.