Microsoft started sending out invitations for a press event that the giant will hold on March 2nd in Barcelona at the 2015 edition of the Mobile World Congress. Windows 10 for smartphones is likely to be the main highlight, but new Lumia handsets could be announced as well.
http://www.notebookcheck.net/Microsoft-MWC-2015-press-event-scheduled-for-March-2.136077.0.html