I've been playing Nexuiz and it keeps asking me to update to 2.4.2.My question is how do i update?

Since you didn't specify your OS and the way you installed nexuiz, I won't be exhaustive.

Download the last and full version here :
http://downloads.sourceforge.net/nexuiz/nexuiz-242.zip

Unzip it, eventually retrieve your old dlcache/ folder and config.cfg file, and play.

You can also use a patch, read the instruction from the download page :
http://alientrap.org/nexuiz/downloads.php

Thank You so much i cant wait to play.