We've recently introduced a new feature where, if a user's phone number has been carrier filtered, we give them a new phone number to send texts out on so they do not continue to be filtered. This is essential in messages continuing to go out. When text message gets filtered by the carrier, the likelihood that this phone number is filtered again increases. Because students are receiving messages from new numbers, that means that the original number was filtered and we gave the user a new one to ensure that all of the outbound messages will send.
For advisor numbers: We still keep the original number for inbound messaging purposes. This means that if the user has the number written down or published anywhere, students can still text into that number and those messages will make it to the user's inbox. Because that number is unreliable for outbound messages though, we won't continue to send messages from that number. They will come from a new number.
For department numbers: we keep a number that has been carrier filtered to receive inbound messages if that number continues to be texted. If a department number that has been carrier filtered does not receive an inbound message for 30 days, we will release that number.
We recognize that messages coming from multiple numbers can be a little confusing, but with carrier filtering, it's possible that messages will not go out at all if we stick to one number. We take this approach to ensure as many messages can go out as possible.