Nope, Xournal has not yet been updated to Diablo.
I am working on it (I am also integrating some changes I made lately) and it's now available only on the Diablo Maemo extras-devel repository.

This repository is not intended for the final users.

When Xournal we'll be ready from prime time again, I'll promote it to maemo extras.
Until then, I won't make any promises of it functioning (in fact, it doesn't right now).

Uninstall this version, disable the Diablo Maemo extras-devel repository and re-install the chinook version.

When the diablo version starts to work fine again, I will announce it and after a period of beta-testing I will promote it for official release.

thanks.