In that thread ( Certbot 0.21.0 Release closed now ) a question was asked about cerbot package for debian update.
The actual version in the debian packages is certbot --version certbot 0.10.2.
On January 24, 2018, a question was asked from @bmw to @hlieberman and never answered.
Any clues 3 month laters ??
Asking since good V is 0.24.0 now and it would be nice to have a up to date package.