It seems that in my viewer group IMs aren’t working. That means that you won’t be able to receive or join group IM sessions. Normal IM from one person to another will work fine though.
I tried the unmodified source and it has the same problem. Trying to figure out now what is going wrong.
Update: Finally figured it out!
The viewer has something called the “message template”. This is a file that lists the various messages that SL uses to communicate with the grid and their format (field names, datatypes, etc). It is located in app_settings/message_template.msg.
The build instructions tell you to copy the file to its final location. This file is mandatory to have, and the viewer will complain loudly and exit with a fatal error if missing.
In the 1.18 version, the “message liberation” happened. Now new viewers can continue working on a grid that has more features than they support. I’ve not yet investigated the technical details very througly, but the basic idea seems quite simple: The viewer simply ignores the messages it doesn’t recognize. So for example, 1.18.1 adds the userlist to IMs. A 1.18.0 viewer doesn’t reconize the messages that send the list of participants, but can still join conversations.
Now, in 1.18 a new file was added: message.xml, and it seems to hold the messages that aren’t in message_template.msg. For some strange reason, missing it doesn’t cause a fatal error, so if it’s not there what happens is that the viewer fails to recognize anything that’s listed in it, which includes group IM messages, which apparently moved to this file in 1.18.
The build instructions I linked above don’t reference this file, and to my knowledge nobody mentioned it was necessary. Other people’s viewers are installed by overwriting an original install, which of course comes with the file correctly packaged, so they didn’t have this problem.
So, fix for the group IMs: Copy the app_settings/message.xml file from a standard SL install to mine.
I will be working on releasing an updated installer.
Update 2: Viewer released. It only contains a fix for this issue.