Guess: the new version was installed in /usr/local (in particular, it installed /usr/local/bin/qmake), since you didn't specify a location. (/usr/local is probably the right place.) The distribution-provided qmake is in /usr/bin/qmake. Your running shell has cached the information that qmake is /usr/bin/qmake. Run hash qmake to make it refresh its cache. A new shell instance will find /usr/local/bin/qmake, as long as /usr/local/bin is ahead of /usr/bin in the $PATH (which it should be).