How to check crontab edited date and time?

Shell Programming and Scripting
1

How to check when was the last time the crontab was updated and also what was the modification done ?

2

you will never know what changes where done in crontab, unless you save the actual crontab away, and in case of a change, compare the original with the changed one, per diff or manually

for the last modification time:

ls -l /var/spool/cron/user1

for example

path may differ from os to os

3

On solaris OS

ls -l  /var/spool/cron/crontabs/user