Short answer:
   I don't think there have been any major changes, but many, many small changes,
   most notably to security.

right now 1.8.4 feels as stable as 1.8.3, so if security is a main concern for you
and you are still running 1.8.2 then switching right now to "stable_snapshot"
at http://www.ruby-lang.org/en/20020102.html will probably work for you. But
it requires compiling.

On the other hand, if you can wait till Christmas the official stable version
will be available, probably with a few precompiled binaries.

Changelog can be found here,
   http://www.ruby-lang.org/cgi-bin/cvsweb.cgi/ruby/ChangeLog?rev=1.2673.2.1437;content-type=text%2Fplain



Joe Van Dyk wrote:

> Is there any place that summarizes the major differences between Ruby
> 1.8.2 and Ruby 1.8.4?
> 
> I've got Ruby 1.8.2 installed in a bunch of places and am wondering if
> it's worth it to upgrade.
> 
> Thanks,
> Joe
> 
>