Starting with version 2.2, the Framework includes the msfupdate online update utility. This script can be used to download and install the latest version of the Framework from the metasploit.com web site. It performs per-file updates by comparing local file checksums with those available from the web site. This process occurs across a validated SSL connection, assuming that the Net::SSLeay module has been installed. This is not completely fail-safe and still depends on the security of the metasploit.com web server. To learn more about the msfupdate tool, simply execute it with the -h argument.
If you would prefer to not use the online update system, you can still download updated modules and the current stable snapshot package from the metasploit.com web site. At this time, msfupdate does not support proxy servers.