I am using Xlite as the softphone in the advanced options- agent
system:general:add_OS_version_to_user_agent_header
value is 0 what to write.
to use magicjack SIP
agent in Xlite
Moderators: Bill Smith, Pilot
The Search button is your friend. Had you bothered to use it to search for "user agent" you would have found this thread, and you would already have your answer.