mjhjmtu

Wikipedia says

With the advent of the GNU Project and Linux, new crons appeared. The
most prevalent of these is the Vixie cron, originally coded by Paul
Vixie in 1987. Version 3 of Vixie cron was released in late 1993.
Version 4.1 was renamed to ISC Cron and was released in January 2004.
Version 3, with some minor bugfixes, is used in most distributions of
Linux and BSDs.

In 2007, Red Hat forked vixie-cron 4.1 to the cronie project and
included anacron 2.3 in 2009.

Other popular implementations include anacron and dcron. However,
anacron is not an independent cron program. Another cron job must call
it. dcron was made by DragonFly BSD founder Matt Dillon, and its
maintainership was taken over by Jim Pryor in 2010.[9]

A webcron solution schedules ring tasks to run on a regular basis
wherever cron implementations are not available in a web hosting
environment.

On Lubuntu 18.04, I try to figure out what my cron implementation is, like for any other software installed, but fail:

$ cron --version
cron: invalid option -- '-'
usage: cron
$ crontab --version
crontab: invalid option -- '-'

I seldom have difficulty in finding out the version of a installed program, and wonder why it is hard for me? How shall I find it out?

Thanks.

Try man cron. It identifies my system's (Ubuntu 18.04)cron as Vixie Cron.