On Thursday, March 7 at 00:00 a.m. UTC, an event data update patch will be
released that will contain several bug fixes.

The newest version of MONSTER HUNTER: WORLD released tomorrow
will be revision number 166925. (The current version is revision number 166849.)
You can verify the version number in the top-left corner when you launch the game
in windowed mode.
Keep in mind that you can only match with other players who have the same
update version as you.

Important:

For other questions, please visit the official MONSTER HUNTER: WORLD support portal below.
http://www.capcom.com/mhwsupport/