The contact form should work - when did you send your message in? (I've moved your message to the Community sites forum - no need to do anything; just letting you know.)
Mary Cooch (personal account)
Повідомлення, що надісла(ла)в Mary Cooch (personal account)
Yes I agree with Emma - see the note in the docs you referenced:
Relative dates mode cannot be enabled for existing courses.
Moodle in English -> Assignment -> File submissions default type. setting not working -> File submissions default type. setting not working
Why not try on the sandbox sites? (https://sandbox.moodledemo.net/) They no longer run 4.5 but you can see if it works or not on more up to date versions.
Thanks - I added it to the docs Login settings in case nobody else did.
Moodle in English -> Teaching with Moodle -> How Administrators can answer a questionnaire -> How Administrators can answer a questionnaire
Give them a second account where they only have the student role.