Q:

Do all files get updated on application cache manifest update? or just the changed ones?

If I am using a cache manifest file like so
CACHE MANIFEST:
#version 1.0
products.html
scripts.js
styles.css

And then I make changes to scripts.js but DO NOT change products.html OR styles.css.  I then update the commented version number, so now my manifest file looks like so
CACHE MANIFEST:
#version 1.1
products.html
scripts.js
styles.css

The question is:  will all three files get downloaded? or only the scripts.js file that changed?

A:

Well according to this website: 

When updating an existing appcache, the browser sends standard
  If-Modified-Since headers, so it skips re-downloading files that have
  not changed.

However, I would really like a more authoritative source if possible before closing the question.

