Neelanshu,
Thanks for your interest in Instantbird.
Offline messages should work fine, I receive them on GTalk and AIM, at
least. What specific protocol are you having issues with?
Note that "offline messages" isn't really a client side thing, the
server/network your connected to also has to support them. If it does,
we should get them when you next log in. At least on all protocols I've
seen.
Please let us know if you have more issues,
Patrick