We checked but we can't find an app the does this feature which we think will be very useful.
Below are the details of our request:
1. Add a phone verification function when a client signs-up where a code will be sent to the client's phone number during registration for new users. There is already a plugin for this but it does not support the next features we will describe.
2. For existing clients, it is very likely that they change phone number after a few months or years. So we need to ensure that they have a way to re-verify their phone number. So they can edit their phone number in their profile and re-verify again.
3. Every 6 months (or can be configured in different cycles) where clients are required to re-verify to ensure that they are maintaining an active number. Maybe this will show up as a prompt or popup after 6 months the last time they verified their phone number where they enter a code sent to their phone to be reverified.
Basically, the objective is to ensure that the phone number that we have on file for the clients are active so we can contact them whenever necessary.