How do I cleanly upgrade my current installation of pd-extended to the new one? I'm on Ubuntu Studio Gutsy.

unless pd-extended is horribly broken, it should be something like:

sudo aptitude remove pd-extended # or whatever the package is called
sudo dpkg -i /path/to/pd-extended-new.deb

@ClaudiusMaximus said:

unless pd-extended is horribly broken, it should be something like:

sudo aptitude remove pd-extended # or whatever the package is called
sudo dpkg -i /path/to/pd-extended-new.deb

Yep, that should do... the .deb packages are at:
http://puredata.info/downloads

Thanks! The only problem is that when I do dpkg, it tries to remove vanilla Pd, and then says that ubuntustudio-audio depends on it:

Selecting previously deselected package pd-extended.
dpkg: considering removing puredata in favour of pd-extended ...
dpkg: no, cannot proceed with removal of puredata (--auto-deconfigure will help):
ubuntustudio-audio depends on puredata
puredata is to be removed.
dpkg: regarding .../Pd-0.40.3-extended-ubuntu-gutsy-i386.deb containing pd-extended:
pd-extended conflicts with pd
puredata provides pd and is present and installed.
dpkg: error processing /tmp/Pd-0.40.3-extended-ubuntu-gutsy-i386.deb (--install):
conflicting packages - not installing pd-extended
Errors were encountered while processing:
/tmp/Pd-0.40.3-extended-ubuntu-gutsy-i386.deb

What should I do?

OK, everything's under control now; I removed the conflicting packages. I also had to fix some other dependency issues after installing (wasn't sure how to do it in the terminal, so I used "fix broken package" in the Synaptic GUI), and now I have the new pd-extended installed.

Thanks for the help! The new version looks excellent so far.

Even simpler -
the conflict in package management is with the Ubuntu-Studio-Audio meta package, which is one-way dependency allowing the quick install of a set of packages. If you allow the removal of the meta-package it DOES NOT remove the constituent packages.
So I just allowed Synaptic to progress as normal.
So no need to 'fix' anything!

Yeah, I hadn't realized when I posted this thread that ubuntu-studio-audio was a meta package, but I took a wild guess that it was and turned out to be right.