Oh, yes, e-mail is mentioned in posts 2, 36, 39 and 49, and in post 58 a distinction is drawn between the value of mail and Whatsapp. That's why I asked.Actually, I don't think any poster wrote "mail" in this thread previously. I'm not a legal expert, but my guess would be an equivalent message over either Whatsapp or email would have the same legal status. Emails, in general, do tend to be more thorough with Whatsapp generally just a few words or short sentences.
Please, would one of the lawyers confirm: Is e-mail regarded as sufficient, as having put things in writing? Or does it have to be paper, presumably delivered to the designated premises before the deadline?