<s>
Android	B-Application
KitKat	I-Application
is	O
the	O
codename	O
for	O
the	O
eleventh	O
Android	B-Application
mobile	I-Application
operating	O
system	O
,	O
representing	O
release	O
version	O
4.4	O
.	O
</s>
<s>
Unveiled	O
on	O
September	O
3	O
,	O
2013	O
,	O
KitKat	B-Application
focused	O
primarily	O
on	O
optimizing	O
the	O
operating	O
system	O
for	O
improved	O
performance	O
on	O
entry-level	O
devices	O
with	O
limited	O
resources	O
.	O
</s>
<s>
The	O
first	O
phone	O
with	O
Android	B-Application
KitKat	I-Application
was	O
the	O
Nexus	B-Device
5	I-Device
.	O
</s>
<s>
1.39	O
%	O
of	O
Android	B-Application
devices	O
run	O
KitKat	B-Application
.	O
</s>
<s>
it	O
is	O
the	O
oldest	O
Android	B-Application
version	I-Application
still	O
supported	O
by	O
Google	B-Application
Play	I-Application
Services	I-Application
and	O
is	O
currently	O
the	O
minimum	O
version	O
to	O
develop	O
apps	O
for	O
the	B-Application
Google	I-Application
Play	O
Store	O
.	O
</s>
<s>
Android	B-Application
4.4	I-Application
"	O
KitKat	B-Application
"	O
was	O
officially	O
announced	O
on	O
September	O
3	O
,	O
2013	O
.	O
</s>
<s>
The	O
release	O
was	O
internally	O
codenamed	O
"	O
Key	O
lime	O
pie	O
"	O
;	O
but	O
John	O
Lagerling	O
,	O
director	O
of	O
Android	B-Application
global	O
partnerships	O
,	O
and	O
his	O
team	O
,	O
decided	O
to	O
drop	O
the	O
name	O
,	O
arguing	O
that	O
"	O
very	O
few	O
people	O
actually	O
know	O
the	O
taste	O
of	O
a	O
key	O
lime	O
pie	O
"	O
.	O
</s>
<s>
Aiming	O
for	O
a	O
codename	O
that	O
was	O
"	O
fun	O
and	O
unexpected	O
"	O
,	O
his	O
team	O
pursued	O
the	O
possibility	O
of	O
naming	O
the	O
release	O
"	O
KitKat	B-Application
"	O
instead	O
.	O
</s>
<s>
The	O
partnership	O
was	O
not	O
revealed	O
publicly	O
,	O
or	O
even	O
to	O
other	O
Google	B-Application
employees	O
and	O
Android	B-Application
developers	O
(	O
who	O
otherwise	O
continued	O
to	O
internally	O
refer	O
to	O
the	O
OS	O
as	O
"	O
KLP	O
"	O
)	O
,	O
until	O
its	O
official	O
announcement	O
in	O
September	O
.	O
</s>
<s>
As	O
part	O
of	O
the	O
promotional	O
efforts	O
,	O
Kit	O
Kat	O
bars	O
in	O
the	O
shape	O
of	O
the	O
Android	B-Application
robot	O
logo	O
were	O
produced	O
,	O
while	O
Hershey	O
ran	O
a	O
contest	O
in	O
the	O
United	O
States	O
with	O
prizes	O
of	O
Nexus	B-Device
7	I-Device
tablets	O
and	O
Google	B-Application
Play	I-Application
Store	I-Application
credit	O
.	O
</s>
<s>
The	O
Nexus	B-Device
5	I-Device
,	O
developed	O
by	O
LG	O
Electronics	O
,	O
was	O
unveiled	O
on	O
September	O
30	O
,	O
2013	O
,	O
as	O
the	O
launch	O
device	O
for	O
KitKat	B-Application
.	O
</s>
<s>
Up	O
to	O
October	O
2017	O
,	O
Android	B-Application
4.4	I-Application
was	O
still	O
supported	O
with	O
security	O
patches	O
by	O
Google	B-Application
for	O
the	O
source	O
code	O
.	O
</s>
<s>
Continuing	O
on	O
from	O
the	O
focus	O
on	O
improving	O
visual	O
performance	O
and	O
responsiveness	O
on	O
Android	B-Application
4.1	I-Application
"	I-Application
Jelly	I-Application
Bean	I-Application
"	I-Application
,	O
the	O
main	O
objective	O
of	O
Android	B-Application
4.4	I-Application
was	O
to	O
optimize	O
the	O
platform	O
for	O
better	O
performance	O
on	O
low-end	O
devices	O
,	O
without	O
compromising	O
its	O
overall	O
capabilities	O
and	O
functionality	O
.	O
</s>
<s>
The	O
initiative	O
was	O
codenamed	O
"	O
Project	O
Svelte	O
"	O
,	O
which	O
Android	B-Application
head	O
of	O
engineering	O
Dave	O
Burke	O
joked	O
was	O
a	O
weight	O
loss	O
plan	O
after	O
Jelly	B-Application
Bean	I-Application
's	O
"	O
Project	O
Butter	O
"	O
added	O
"	O
weight	O
"	O
to	O
the	O
OS	O
.	O
</s>
<s>
To	O
simulate	O
lower-spec	O
devices	O
,	O
Android	B-Application
developers	O
used	O
Nexus	B-Device
4	I-Device
devices	O
underclocked	B-Device
to	O
run	O
at	O
a	O
reduced	O
CPU	O
speed	O
with	O
only	O
a	O
single	O
core	O
active	O
,	O
512MB	O
memory	O
,	O
and	O
at	O
960×540	O
display	O
resolution	O
—	O
specifications	O
meant	O
to	O
represent	O
a	O
common	O
low-end	O
Android	B-Application
device	O
.	O
</s>
<s>
This	O
data	O
was	O
used	O
to	O
optimize	O
and	O
decouple	O
Google	B-Application
apps	O
and	O
services	O
found	O
to	O
be	O
inefficient	O
,	O
thus	O
helping	O
to	O
reduce	O
the	O
overall	O
memory	O
usage	O
of	O
Android	B-Application
.	O
</s>
<s>
The	O
overall	O
interface	O
of	O
KitKat	B-Application
further	O
downplays	B-Device
the	O
"	O
Holo	O
"	O
interface	O
appearance	O
introduced	O
on	O
4.0	B-Application
,	O
replacing	O
remaining	O
instances	O
of	O
blue	O
accenting	O
with	O
greys	O
and	O
white	O
(	O
such	O
as	O
the	O
status	O
bar	O
icons	O
)	O
,	O
and	O
getting	O
rid	O
of	O
the	O
Wi-Fi	O
upstream	O
and	O
downstream	O
traffic	O
indicators	O
(	O
triangles	O
pointing	O
up	O
and	O
down	O
)	O
,	O
though	O
they	O
can	O
still	O
be	O
seen	O
in	O
the	O
quick	O
control	O
center	O
menu	O
.	O
</s>
<s>
The	O
appearance	O
may	O
deviate	O
in	O
custom	O
vendor	O
distributions	O
such	O
as	O
TouchWiz	B-Application
.	O
</s>
<s>
On	O
stock	O
devices	O
,	O
the	O
Messaging	O
and	O
Movie	O
Studio	O
apps	O
were	O
removed	O
;	O
the	O
former	O
was	O
replaced	O
by	O
Google	B-Protocol
Hangouts	I-Protocol
,	O
which	O
supported	O
SMS	B-Device
.	O
</s>
<s>
The	O
AOSP	O
Gallery	O
app	O
was	O
also	O
deprecated	O
in	O
favor	O
of	O
Google+	B-Algorithm
Photos	I-Algorithm
.	O
</s>
<s>
A	O
new	O
runtime	B-Device
environment	I-Device
known	O
as	O
the	O
Android	B-Application
Runtime	I-Application
(	O
ART	O
)	O
,	O
intended	O
to	O
replace	O
the	O
Dalvik	B-Application
virtual	I-Application
machine	I-Application
,	O
was	O
introduced	O
as	O
a	O
technology	O
preview	O
in	O
KitKat	B-Application
.	O
</s>
<s>
ART	O
is	O
a	O
cross-platform	O
runtime	O
which	O
supports	O
the	O
x86	B-Operating_System
,	O
ARM	B-Architecture
,	O
and	O
MIPS	B-Device
architectures	I-Device
in	O
both	O
32-bit	O
and	O
64-bit	B-Device
environments	O
.	O
</s>
<s>
Unlike	O
Dalvik	B-Application
,	O
which	O
uses	O
just-in-time	O
compilation	O
(	O
JIT	O
)	O
,	O
ART	O
compiles	O
apps	O
upon	B-Application
installation	I-Application
,	O
which	O
are	O
then	O
run	O
exclusively	O
from	O
the	O
compiled	O
version	O
from	O
then	O
on	O
.	O
</s>
<s>
KitKat	B-Application
also	O
supports	O
zram	B-Application
.	O
</s>
<s>
WebView	O
components	O
were	O
updated	O
to	O
utilize	O
a	O
version	O
of	O
the	B-Application
Google	I-Application
Chrome	B-Application
rendering	B-Language
engine	I-Language
.	O
</s>
<s>
Sensor	B-Application
batching	I-Application
,	O
step	O
detection	O
and	O
counter	O
APIs	O
were	O
also	O
added	O
.	O
</s>
<s>
KitKat	B-Application
supports	O
host	O
card	O
emulation	O
for	O
near-field	O
communications	O
,	O
which	O
allows	O
apps	O
to	O
emulate	O
a	O
smart	O
card	O
for	O
activities	O
such	O
as	O
mobile	O
payments	O
.	O
</s>
