Multi-touch was the main feature of X Input 2.2 with X.Org Server 1.12 as released at the beginning of the month. Development versions of the xf86-input-synaptics driver that support multi-touch have been available, but now this driver has moved onto its release candidate phase in preparation for a stable release in the near future. Besides needing a supportive X.Org Server (version 1.12 or Canonical's backported-Xi2.2-on-server-1.11 for Ubuntu 12.04), mtdev is also required for multi-touch support. Multi-touch Protocol Translation Library -- mtdev -- translates the kernel input event stream into a simplified manner for the driver to handle.
The other key feature of the forthcoming Synaptics 1.6 is ClickPads support, which are like fake buttons. Read this article to learn about Clickpads with the Synaptics X.Org driver.
Like the xf86-input-evdev driver, the new Synaptics driver also has initial support for smooth scrolling as found in X.Org Server 1.12. That code has been around since last year.
Find out more about the xf86-input-synaptics 1.6 release candidate in this mailing list announcement.