This post comes via notes taken from another blog… seemingly gone awol. Here for posterity.
Etch naturally has an older version of WordPress. To upgrade to a more recent, possibly though unlikely more secure version, the easiest way is to change your tracking to testing, install WordPress and then change back. How to do it:
1. Edit your /etc/apt/sources.list to track testing. If your sources.list says etch or stable, change that to testing. For example if your source.list has:
deb http://debian.lcs.mit.edu/debian etch main contrib non-free
deb-src http://debian.lcs.mit.edu/debian etch main contrib non-free
change those to:
deb http://debian.lcs.mit.edu/debian testing main contrib non-free
deb-src http://debian.lcs.mit.edu/debian testing main contrib non-free
2. After you change your tracking to testing do an apt-get update.
3. Install WordPress
apt-get install wordpress
this may pull in a few new php libraries, such as libphp-phpmailer. Let it.
(Note that you do not want to do an “upgrade”, but rather “install” as listed above. “upgrade” will try to upgrade a ridiculous number of packages, whereas install will focus only on packages required for installing and/or upgrading WordPress.)
4. Change your tracking back to Etch. just reverse what you did in step 1. that is change testing back to etch.
5. Clean everything up.
apt-get clean && apt-get update
After all this is done, login back in as admin to WordPress, and it will tell you that you have to update your WordPress database tables. Do that and you’re done.