The update doesn't seem to affect freeways or divided highways; in those circumstances, the overall Autopilot speed limit of 90 mph still applies.
The Autopilot update comes on the heels of a recent 8.0.2 update, which adds some convenience features that users will probably appreciate. One allows the maps application to display restaurants, shopping, and other locations near a Supercharger station to make those stops more convenient. The other update links an owner's profile to an individual key fob, which saves the hassle of switching profiles if more than one driver uses the vehicle.
This is all happening while we're waiting for the Enhanced Autopilot that we were in mid-December, but we're still in a holding pattern on that. Stay tuned.