1. on the message
one grey tick: device (mobile or web) received a message from typer
small clock: device (mobile or web) trying to send to server (on mobiles, if you go to another app the system will stop the transmission and will reestart the next time you open immail)
two grey ticks: the server received the message and sent to the recipient (the other guy on a private chat or the group)
two green ticks: the other guy on a private chat or someone on the group have opened the chat or group.
2. badge on the top of menu (over “CHATS”)
the number means how many messages are available to be seen
3. badge on the right side of group/user name
the number means how many messages are available to be seen
4. badge on the app (mobile only)
the number means how many messages are available to be seen
that number will be zeroed the next time you open imMail app, no matter you open the group/chat or not