there are only two member in room, one is iphone safari explorer, and one is windows edge explorer.
all the time the connections seem to use jvb as we see the following in connection details:

As a contrast,when the 2 member are all from windows pc explorer ( one is chrome , another is edge), the connection mode is p2p.
I tried may times, and the results were the same. Anyone can help? Thanks!
This is normal. p2p had been turned off for some time from mobile till the mobile transition from plan-b to unified plan. This was needed as unified is now the default for the backend.
We are actively working on that and we expect soon to finish that and publish it in the mobile apps.
Thank you very much for your reply @damencho . And Currently, how should I configure to enable mobile device browser participants to enable p2p mode?Or just wait for the new version of jitsi server to be published?