Some getting sms some not get messages

[flipbeats]

Anyone figure out why some people with Android don't get the message and some do. While a lot of iPhones are getting my messages and some don't. I'm thinking maybe it has to do with how old the phone is. I know Google is working it's allo messages from an update so you receive the messages regardless if you have allo installed or not. my friend has a moto x 2015 and he doesn't get my messages.