The Roberts Space Industries website has details on a new alpha version 1.3 build of Star Citizen that's now available for backers of Cloud Imperium's space exploration and combat game. They offer details on some new weapons available in the new version, but note that many of the changes in the patch are "under the hood" as they combine different development streams to pave the way for their upcoming alpha 2.0 "Mini Persistent Universe" release. They also offer a new Development Update with details on their progress towards alpha 2.0 as well as the Star Marine module. There are other visible changes in alpha 1.3, however, as they explain in this bit:

In addition to technical work, today’s patch includes updates to the flight model, a selection of new, larger guns for Voyager Direct and a variety of other changes.

The patch is currently accessible via the Star Citizen Launcher and a complete list of release notes (including balance modifications, known issues and other changes) are available here.