i have installed 4.1.
and on MAC About i see 4.01 ??
This is true also on Windows, and like bertus oud said, the installer does not overwrite previous installations, it installs a new. I find that useful at times, you can always start the older versions if you like to.
You are most likely using the same shortcut as previous to installing 4.1.1, thus you are opening the old version.