Andre, Ubuntu 16.04 LTS included evolution-dats-server 3.18. 3.20 introduced a major overhaul of Google oauth2 integration. So a fix in 3.28.3 is probably not going to be easy to apply to 16.04 LTS.
cement_head, I encourage you to upgrade to Ubuntu 18.04 LTS which has many improvements in Evolution.
Andre, Ubuntu 16.04 LTS included evolution- dats-server 3.18. 3.20 introduced a major overhaul of Google oauth2 integration. So a fix in 3.28.3 is probably not going to be easy to apply to 16.04 LTS.
cement_head, I encourage you to upgrade to Ubuntu 18.04 LTS which has many improvements in Evolution.