what is group message ?

OK, it is becoming clear now and all makes somehow sense.

Pity only, that all is called a message by default. One has to realize this and select 'post' when sending a message when the phone is incidentally connected to internet, otherwise it becomes like CC and replay to all in email.

I wish there would be a clear selection for group message in the app an only when clearly a group message is selected it should be created.

Sending simply what seems obvious a message with multiple recipients and ending in CC-replay to all is too bad.

There should be simply an extra switch called group message.

At least we are protected against sending it via satellite.

I don't think you really are protected. If the SMS recipient (that is, the recipient's Messenger app) is out of cell and WiFi coverage, the message is going to that recipient via satellite. Or so I understand it. Same thing with the sender - if you're out of range, the outbound message will go via iR. Would guess that there is only one outbound message no matter how many recipients.

As far as terminology goes, I THINK they could just change the labels on the buttons: Message > Group Message, Post > Message. They would also have to enable Post/Message even when there is only one recipient. That limitation might be a bug already - who knows?

we will see, it is not ergonomic at all

I will try to run some tests.

So far I tested to set the phone to 'airplane' but switch on the BT only. When I select a recipients, phone numbers only, this will be transmitted via IR definitely. But as far as I understand the explanations of Leslie and other texts, this will be transmitted as normal message, or we should read it as 'post'. Subsequent communication will not be propagated (CC & raplay to all) but will become just normal point to point communication.

But yes, the labeling of the task is in fact somehow wrong, as general public will understand word post and message quite opposite way as I tested now on 6 persona independently when letting them to see what the app does.

Summary:

Group messaging will only work through the messenger app and only with sms phone numbers. None of the inReach devices allow for group messaging through satellite communication. The messenger itself along with the IR widget strictly uses single satellite messages. The messenger app allows for group messaging solely in the app because it uses wifi and cellular data to transmit. For me, that means the reverse: if you don't have a wifi/cellular connection, you can't send a group message (but you can send a message to some people via satellite (sent/delivered/charged each as a single message).

At least that's how I understand it now. Correct?

But maybe that's all nonsense what I wrote, because I'm just too stupid to get it. 

@Garmin-Leslie: I am quit sure that I have had a group message chat with 2 people only via satellite. I will ask Ranleigh in a different forum

Volker said:

At least that's how I understand it now. Correct?

yes I agree on that, this seems to be the correct behavior.

Strange enough, I produced some messages to multiple recipients, some of them being addressed to iR, SMS and email.

This seemed to me did also produce group message, just because there were phone numbers involved. Result was that messages from those recipients arrived also on the phone of the origin of the initial message.

I think there should be a clear button: group message

When creating such msg which does not comply with the specs for group message, a warning or information should be displayed: this message can not be sent as group message

OK, thanks to your dev sources for the clarification

now we at least know where to start any discussion on this subject

now we know, we have to be careful with group messaging, as this can produce lot of expensive traffic

The wish to the devs now:

in the app, name one button group message and the other normal message or so. Message and Post have no meaning and nobody does understand it in fact as you can see.