Official *binaries* of this product released by the Instantbird team
(http://www.instantbird.com/) are made available under the GNU General
Public License GPL version 2.0 or later.

All of the *source code* for this product is available under licenses
which are both free and open source.

Most is available under one of the following:
 - the Mozilla Public License (MPL) 2.0,
 - the GNU General Public License (GPL) 2.0 or later,
 - the GNU Lesser General Public License (LGPL) 2.1 or later.

The remainder of the software is available under a variety of more permissive
licenses.

See about:license for details.