[Koha] How to update

[ICT Helpdesk Waimate Main School]

hey ya

Our small primary school runs Koha and would like to update it as it
has not been done since it was installed years ago.
Koha version:	3.14.01.000
OS version ('uname -a'):	Linux debian 2.6.32-5-686 #1 SMP Mon Sep 23
23:00:18 UTC 2013 i686 GNU/Linux
Perl interpreter:	/usr/bin/perl
Perl version:	5.010001


How do we go about updating to the latest version. I cant seem to find
an update option anywhere.

thanks

Alex