I am going to update those PPA's to 0.8 soon. For now there are multiple options both stable and daily. I don't know about the Deja-dup PPA, but my guess is that it should be up-to-date.
* Stable tarball install -
https://launchpad.net/duplicity/+download* Daily duplicity builds -
https://launchpad.net/~duplicity-team/+archive/ubuntu/daily-dev-trunk* Stable snap builds - “sudo snap install duplicity —classic"
* Latest snap builds - “sudo snap install duplicity —classic —edge"
* Latest pip3 builds - “sudo pip3 install duplicity"
NOTE: UNinstall duplicity first if it was installed via the distribution repository. For Ubuntu that would be "sudo apt-get purge duplicity".