heads up - messaging_type property required from 7th may 2018

[humpfreybogart]

[DELETED]

[pdoggi]

Hi! The May 7th, 2018 is fast approaching. Curious if anyone's up for the challenge? Perhaps we can also include the NON_PROMOTIONAL_SUBSCRIPTION tag in the valid tags list.

Would be up for collaboration this week if anyone can put in some time.

Thanks!!