I have Emacs 24.3.1 and I'd like to upgrade to the latest Emacs 24.4.x. All documentation that I have visited suggests building from a tarball or source. Is there a reason why there are no package manager options to upgrade my Emacs? If not, how do I upgrade my Emacs using the package manager?

Here is some info about my Emacs, which I believe comes default on Ubuntu 14.04:

emacs:

  Installed: 45.0ubuntu1

  Candidate: 45.0ubuntu1

  Version table:

 *** 45.0ubuntu1 0

        500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

        100 /var/lib/dpkg/status