When I select the dovecot-core package in Synaptic, it also wants to install ntpdate. Install packages at the command line using apt-get. It lets you better see and understand what's going on. dovecot-core /recommends/ ntpdate. This means you can install with apt-get --no-install-recommends and the Recommends will be shown but not installed, leaving the judgement to you.
Ahah! OK Thanks.
Now the dovecot-core package evidently requires ntpdate. I can't imagine why this dependency would exist. And I presume this dependency will prevent me from removing ntpdate after I install dovecot-core. In apt-based systems, removing a package triggers removal of any depending packages, but not "recommending" packages. Just try 'apt-get remove ntpdate'. It will prompt you, and quite likely it will say it is about to remove ntpdate and no other package. It will do what it says it is going to do, and no more.
OK. Thanks.
Is the Debian package maintainer on the list? He does read the list. In either case dovecot-core in ubuntu 17.04 and in Debian stretch and jessie don't have this Recommends. I don't know what to do. Any suggestions? Remove ntpdate, you'll be fine.
Great. Thanks!
Michael