Install Dino with test XMPP accounts on separate servers. Exchange messages and attachments, try a group conversation, and check delivery after one client has been offline. Verify device and encryption behavior for the setup you intend to use.
Messaging reliability depends on servers and account recovery as well as the client. Keep a fallback channel for urgent work and document how contacts are re-established after a device loss. Choose it from real cross-server experience, not a single local chat.
Akousa