Qt 4.8.5 in Windows7
I am about to install qt-win-opensource-4.8.4-mingw, but I heard that there is an specific [older] version of MinGW that I need to install, does anyone knows if this is true?
Yes. The Qt 4.8 binaries are built against MinGW 4.4, which is incompatible with the current MinGW 4.8.
A user is kindly mirroring MinGW 4.4 at http://nosymbolfound.blogspot.com.au/2012/12/since-until-now-qt-under-windows-is.html