"WhatsApp announced the change to its terms of service policy today. It allows businesses to communicate with users, including appointment reminders, delivery and shipping notifications and marketing pitches."
Bloomberg Source
I'm thinking that text messaging will still be king for quite some time for the simple reason that it's universal.
The big disadvantage of What'sApp, Telegram, Facebook Messenger and other messaging services is that only some of your residents are going to use them, and only some will have notifications turned on on their phone. Is it worth supporting another platform for a minority of your residents? Personally, I use Facebook Messenger, but I don't have the notifications turned on, so it's not a good way to communicate with me.
We are looking at this though. As my partners are looking for better ways to reach residents, maybe an app will surpass texting as the best way to reach residents. When/if that happens, you can be sure that we'll support it!
You should take a look at Mobile Doorman,, a highly-customized app that is a very robust communication portal for residents. Full disclosure, they are a client of mine; really worth a look-see.