Licensing of Android

The source code for Android is available
under free and open-source software
licenses. Google publishes most of the code
(including network and telephony stacks )[140]
under the Apache License version 2.0, [141]
[142] and the rest, Linux kernel changes,
under the GNU General Public License version
2. The Open Handset Alliance develops the
changes to the Linux kernel, in public, with
source code publicly available at all times.
The rest of Android is developed in private by
Google, with source code released publicly
when a new version is released. Typically
Google collaborates with a hardware
manufacturer to produce a "flagship" device
(part of the Google Nexus series) featuring
the new version of Android, then makes the
source code available after that device has
been released. [143]
In early 2011, Google chose to temporarily
withhold the Android source code to the
tablet-only 3.0 Honeycomb release. The
reason, according to Andy Rubin in an official
Android blog post, was because Honeycomb
was rushed for production of the Motorola
Xoom, [144] and they did not want third
parties creating a "really bad user
experience" by attempting to put onto
smartphones a version of Android intended
for tablets. [145] The source code was once
again made available in November 2011 with
the release of Android 4.0. [146]
Even though the software is open-source,
device manufacturers cannot use Google's
Android trademark unless Google certifies
that the device complies with their
Compatibility Definition Document (CDD).
Devices must also meet this definition to be
eligible to license Google's closed-source
applications, including Google Play . In recent
versions of Android, Google has also stopped
maintaining the open source versions of
certain stock Android apps (including
Calendar, Music, and Search), in favor of
moving further enhancements and primary
development to closed-source variants such
as Google Calendar and Google Play Music. At
the same time, Google Play Services inherits
and introduces development APIs which are
also proprietary. [2][147]
Richard Stallman and the Free Software
Foundation have been critical of Android and
have recommended the usage of alternatives
such as Replicant , because drivers and
firmware vital for the proper functioning of
Android devices are usually proprietary, and
because Google Play allows non-free
software. [148][149]