The Debian package for installing and updating nftfw is now online at the GitHub site. The source code contains the debian directory for building the package, and binary versions of the package for installation. Updating the installation is considerably simpler with the package. I think that this is now my preferred way of updating things.
There is a document Install nftfw from the Debian Package aimed at installing the package, which starts with installation on a vanilla debian system. There are then links to more complex installation scenarios. The source distribution includes a new Uninstall.sh script, and both the source and the binary package include import_to_nftfw.py, a script to process and install settings from the /etc/sympl/firewall directory.
If you use this do check that your config.ini and nftfw_init.nft are updated. Use diff to see what the differences between your versions and the distributed ones.
I’ve submitted the package to Debian for inclusion. However, if you have experience with Debian packaging and can spare the time to look at what I’ve done, then I’d be grateful for any assistance and comments you may have.