At the end of the year 2007 I sent my first patch to KWin. At that time 4.0 was about to be released, so that patch didn’t end up in the repo in 2007, but only in beginning of 2008 and was released with 4.1.
Ten years is a long time and we have achieved much in KWin during that time. My personal highlight is of course that KWin is nowadays a Wayland compositor and no longer an X11 window manager. According to git shortlog I added about 5000 commits to KWin and another 500 commits to KWayland.
So up to the next ten years! Merry Christmas and a happy new year 2018.