calendarserver software package provides Apples Calendar and Contacts Server, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install calendarserver
calendarserver is installed in your system.
Make ensure the calendarserver package were installed using the commands given below,
$ sudo dpkg-query -l | grep calendarserver *
You will get with calendarserver package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Network |
| Package | calendarserver |
| Version | 7.0+dfsg-2 |
| Description | Apples Calendar and Contacts Server |
| Sub Section | Net |