.
Firefox 28 beta is available at
http://www.mozilla.org/en-US/firefox/channel/

This beta purports to transform Iceweasel to Firefox 28 beta capability.
That is, it replaces flash with html5. May need to add flash blocker to
get the whole effect. I am experimenting with IceWeasel 21 so modified.

Caveat Emptor; installation probably not easily reversible.