I noticed there's an update but I'm out of town so I can't install it. Are there any new features or just bug fixes?
nope, just bug fixes.
Some small "tweak" improvements, not necessarily all bug fixes.
I read today in the news that Tesla has released an update to prevent hackers from getting control of the car.
Everybody should have the hacker prevention update as of today.
Please tell us which update you're talking about. Is it (2.5.21)?
Don't know about changes. After the update, Nav worked really weird today. It insisted on shortest distance, not shortest time. Kept taking me on surface streets when highway didn't have traffic congestion. It's done this route many times - this is the first time it did this silliness.
This might have been what the update addressed:
This Wired article confirms the update was to address vulnerabilities exposed by the hackers: http://www.wired.com/2015/08/researchers-hacked-model-s-teslas-already/.