To get newer man pages in OSX?
The best manual is the manual that is supplied with the command you are using whether that manual is old or new. Assuming that you have not hard coded MANPATH then man would determine the manual with your PATH and man.conf. If you are installing your own tools then possibly man.conf may need to be configured with your installation prefix. 

If you have duplicate tools installed then the manual for the command first in your PATH is presented. You can read another manual by pointing man to the directory in which that man page resides.

    man -M /path/to/share/man COMMAND


You can read all the manuals of a particular command.

    man -a COMMAND