Yep. That's from the standard repos. Just use (from a terminal):
Code:
sudo apt-get install sigil
to upgrade to 0.9.8.
NOTE: the "About" dialog for Sigil v0.9.8 from the standard repository will likely indicate that it's v0.9.7. But it really is v0.9.8. We just didn't have the version strings updated when v0.9.8 was tagged for release.