Upgrading from Backports

[Patrick Bartek <nemommxiv@gmail.com>]

Need to upgrade claws-mail installed from regular repo to a newer
version in wheezy-backports.  I don't want to end up with two installed
versions.  Have done research, but have found nothing specific about
this particular procedure.  Would

   apt-get install -t wheezy-backports claws-mail=<newer version number>

upgrade the old version or just install the new version along side the
old.

Or would it be easier to "remove" the old version keeping all the
configs, etc., and install the new one from backports?  I did this with
LibreOffice a few years ago.  Worked fine.

I'm running Wheezy 64-bit.

Thanks.

B