What is a more stable replacement for skype?

Question

Skype

We need a more stable replacement for skype .
Requirements:

1. Clients for Android and iOS
   
2. Group chats up to 200 people
   
3. Audio calls up to 20 people
   
4. Video calls up to 5 people
   
5. The ability to invite a user to a call without prior registration and installation of a desktop client, but through the web version
   

Can you please tell me if there are any good skype alternatives for these requirements?

Answer 1

Haven't tried it, but Discord recommends.

Answer 2

Hangouts