$ wget https://download.kopano.io/community/core%3A/core-10.0.6.349.8669778-Ubuntu_18.04-amd64.tar.gz
$ tar xfz core-10.0.6.349.8669778-Ubuntu_18.04-amd64.tar.gz
$ cd core-10.0.6.349.8669778-Ubuntu_18.04-amd64
$ sudo dpkg -i *.deb
### If apt fails to resolve dependencies:
$ sudo apt install -f