Here are instructions to upgrade AMPL-Gurobi on Mac OS X:
Run the supplied installer for AMPL-Gurobi, which will be named something like amplgurobi6.0.0.pkg. This will install AMPL-Gurobi for all users of your Mac.
If you are using a floating license server for AMPL-Gurobi, please follow the additional instructions for ampl_lic.
