How do I find a previous version of a package to downgrade in Ubuntu?

I suspect a bug in libfreetype6 (version 2.4.4-1ubuntu2.1) is causing my LibreOffice Writer to crash whenever I try to save (as described here), so I want to downgrade it to one of the previous versions开发者_JAVA技巧.

I've tried fiddling with apt-get, apt-cache, aptitude, Ubuntu Software Centre, Synaptic Package Manager but can't get any older version of libfreetype6 out of any of them.

I've tried searching for an old version of libfreetype6 at debian.org, launchpad.net, packages.ubuntu.com, but I don't know how to get those files into one of my package managers to install it properly.

I'm using Ubuntu 11.04 (natty) and my architecture is amd64.

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Download an older version of the package (which should be a .deb file) and save it somewhere

The, run the command:

sudo dpkg -i /path/to/your-package.deb