Hello, how can I let the robot automatically know that a new user has joined the group?

[1104190950]

Hello, how can I let the robot automatically know that a new user has joined the group?
I want to implement the function that the BOT sends a verification code for the user to verify after the new user joins the group

[saqoah]

use
private static final String NEWCHATMEMBERS_FIELD = "new_chat_members";

if ( update.message.newChatMembers.isNotEmpty() ) {
                val newChatMembers = update.message.newChatMembers
                //
}

you get a (Mutable)List<User!>! as a result

[samosxin]

if group is public, Maybe I don't get the update information