<s>
The	O
Apache	B-Application
License	O
is	O
a	O
permissive	B-License
free	I-License
software	I-License
license	I-License
written	O
by	O
the	O
Apache	B-Application
Software	O
Foundation	O
(	O
ASF	O
)	O
.	O
</s>
<s>
The	O
ASF	O
and	O
its	O
projects	O
release	O
their	O
software	O
products	O
under	O
the	O
Apache	B-Application
License	O
.	O
</s>
<s>
Beginning	O
in	O
1995	O
,	O
the	O
Apache	B-Application
Group	O
(	O
later	O
the	O
Apache	B-Application
Software	O
Foundation	O
)	O
released	O
successive	O
versions	O
of	O
the	O
Apache	B-Application
HTTP	I-Application
Server	I-Application
.	O
</s>
<s>
Its	O
initial	O
license	O
was	O
essentially	O
the	O
same	O
as	O
the	O
original	B-License
4-clause	I-License
BSD	I-License
license	I-License
,	O
with	O
only	O
the	O
names	O
of	O
the	O
organizations	O
changed	O
,	O
and	O
with	O
an	O
additional	O
clause	O
forbidding	O
derivative	O
works	O
from	O
bearing	O
the	O
Apache	B-Application
name	O
.	O
</s>
<s>
In	O
July	O
1999	O
,	O
the	O
Berkeley	B-Operating_System
Software	I-Operating_System
Distribution	I-Operating_System
accepted	O
the	O
argument	O
put	O
to	O
it	O
by	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
and	O
retired	O
their	O
advertising	O
clause	O
(	O
clause	O
3	O
)	O
to	O
form	O
the	O
new	O
3-clause	O
BSD	B-Operating_System
license	O
.	O
</s>
<s>
In	O
2000	O
,	O
Apache	B-Application
did	O
likewise	O
and	O
created	O
the	O
Apache	B-Application
License	O
1.1	O
,	O
in	O
which	O
derived	O
products	O
are	O
no	O
longer	O
required	O
to	O
include	O
attribution	O
in	O
their	O
advertising	O
materials	O
,	O
only	O
in	O
their	O
documentation	O
.	O
</s>
<s>
In	O
January	O
2004	O
,	O
ASF	O
decided	O
to	O
depart	O
from	O
the	O
BSD	B-Operating_System
model	O
and	O
produced	O
the	O
Apache	B-Application
License	I-Application
2.0	I-Application
.	O
</s>
<s>
The	O
stated	O
goals	O
of	O
the	O
license	O
included	O
making	O
it	O
easier	O
for	O
non-ASF	O
projects	O
to	O
use	O
,	O
improving	O
compatibility	O
with	O
GPL-based	O
software	O
,	O
allowing	O
the	O
license	O
to	O
be	O
included	O
by	O
reference	O
instead	O
of	O
listed	O
in	O
every	O
file	O
,	O
clarifying	O
the	O
license	O
on	O
contributions	O
,	O
and	O
requiring	O
a	O
patent	O
license	O
on	O
contributions	O
that	O
necessarily	O
infringe	O
a	O
contributor	O
's	O
own	O
patents	O
.	O
</s>
<s>
The	O
Apache	B-Application
License	O
is	O
permissive	B-License
;	O
unlike	O
copyleft	B-License
licenses	I-License
,	O
it	O
does	O
not	O
require	O
a	O
derivative	O
work	O
of	O
the	O
software	O
,	O
or	O
modifications	O
to	O
the	O
original	O
,	O
to	O
be	O
distributed	O
using	O
the	O
same	O
license	O
.	O
</s>
<s>
The	O
Apache	B-Application
License	I-Application
2.0	I-Application
attempts	O
to	O
forestall	O
potential	O
patent	O
litigation	O
in	O
Section	O
3	O
.	O
</s>
<s>
The	O
Apache	B-Application
Software	O
Foundation	O
and	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
agree	O
that	O
the	O
Apache	B-Application
License	I-Application
2.0	I-Application
is	O
a	O
free	B-License
software	I-License
license	I-License
,	O
compatible	O
with	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
version	O
3	O
,	O
meaning	O
that	O
code	O
under	O
GPLv3	O
and	O
Apache	B-Application
License	I-Application
2.0	I-Application
can	O
be	O
combined	O
,	O
as	O
long	O
as	O
the	O
resulting	O
software	O
is	O
licensed	O
under	O
the	O
GPLv3	O
.	O
</s>
<s>
The	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
considers	O
all	O
versions	O
of	O
the	O
Apache	B-Application
License	O
to	O
be	O
incompatible	O
with	O
the	O
previous	O
GPL	B-License
versions	O
1	O
and	O
2	O
.	O
</s>
<s>
Furthermore	O
,	O
it	O
considers	O
Apache	B-Application
License	O
versions	O
before	O
2.0	O
incompatible	O
with	O
GPLv3	O
.	O
</s>
<s>
Because	O
of	O
version	O
2.0	O
'	O
s	O
patent	O
license	O
requirements	O
,	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
recommends	O
it	O
over	O
other	O
non-copyleft	B-License
licenses	O
.	O
</s>
<s>
If	O
the	O
Apache	B-Application
License	O
with	O
the	O
LLVM	O
exception	O
is	O
used	O
,	O
then	O
it	O
is	O
compatible	O
with	O
GPLv2	O
.	O
</s>
<s>
In	O
October	O
2012	O
,	O
8,708	O
projects	O
located	O
at	O
SourceForge.net	B-Application
were	O
available	O
under	O
the	O
terms	O
of	O
the	O
Apache	B-Application
License	O
.	O
</s>
<s>
In	O
a	O
blog	O
post	O
from	O
May	O
2008	O
,	O
Google	B-Application
mentioned	O
that	O
over	O
25%	O
of	O
the	O
nearly	O
100,000	O
projects	O
then	O
hosted	O
on	O
Google	B-Protocol
Code	I-Protocol
were	O
using	O
the	O
Apache	B-Application
License	O
,	O
including	O
the	O
Android	B-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
,	O
according	O
to	O
Black	O
Duck	O
Software	O
and	O
GitHub	B-Application
,	O
the	O
Apache	B-Application
license	O
is	O
the	O
third	O
most	O
popular	O
license	O
in	O
the	O
FOSS	B-License
domain	O
after	O
MIT	B-License
License	I-License
and	O
GPLv2	O
.	O
</s>
<s>
The	O
OpenBSD	B-Operating_System
project	I-Operating_System
does	O
not	O
consider	O
the	O
Apache	B-Application
License	I-Application
2.0	I-Application
to	O
be	O
an	O
acceptable	O
free	O
license	O
because	O
of	O
its	O
patent	O
provisions	O
.	O
</s>
<s>
The	O
OpenBSD	B-Operating_System
policy	O
believes	O
that	O
when	O
the	O
license	O
forces	O
one	O
to	O
give	O
up	O
a	O
legal	O
right	O
that	O
one	O
otherwise	O
has	O
,	O
that	O
license	O
is	O
no	O
longer	O
free	O
.	O
</s>
