Ask HN: How do you manage communication with your userbase?

Hi all,

Our mobile app has surpassed 250k MAU (monthly active users) and our home grown communications service designed when we had approx 10k MAU is lagging behind.

Our communications service is responsible for sending transactional in-app and e-mail notifications.

We are evaluating two alternatives:

1) Redesign our communications service

2) Integrate with a CRM product (offloading some development)

So, how are you managing communications with your userbase? Can you share your learnings in using one or the other approach, specially with regards to usability, development flexibility and cost?

Thanks in advance!