XMPP Carbons and Mobile Optimization


I've been doing a little more research 
into Prosody modules, which add features 
to the server. It turns out that for the 
message carbons feature to send updates 
to clients that were logged off when the 
messages were sent, message logs must be 
stored on the server. I have not enabled 
that feature -- intentionally -- because 
I view storing chat logs as a potential 
privacy problem. So, if you want all 
messages delivered to all clients, 
you'll have to keep them all logged in.

Another set of features which we did not 
have on the Prosody server are 
optimizations designed to save battery 
and bandwidth on mobile devices. Three 
new modules are now enabled for that 
purpose. If you're interested in looking 
them up, they're mod_csi, 
mod_throttle_presence, and 
mod_filter_chatstates. In general, they 
filter out insignificant data when your 
client is inactive (like user state 
changes -- online, busy, away, etc.). If 
these modules cause headaches for 
anyone, just let me know and I'll 
disable them again.