How stable is an API endpoint if it's in BETA?

This is Ted from Hashsnap, a master reseller in South Korea.
I’m forwarding a question from my client who are interested in the Get all activities (BETA) endpoint.

1. How stable is this endpoint?
I know this is in BETA, but how buggy is this? Can I test it for my integration?

2. Do you have any release schedule for BETA endpoints?
My client is wondering whether you have any timetable for release schedule.

Let me know in case you need more information.