<s>
iOS	B-Operating_System
(	O
formerly	O
iPhone	B-Operating_System
OS	I-Operating_System
)	O
is	O
a	O
mobile	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
developed	O
by	O
Apple	O
Inc	O
.	O
exclusively	O
for	O
its	B-Operating_System
hardware	I-Operating_System
.	O
</s>
<s>
It	O
is	O
the	O
operating	O
system	O
that	O
powers	O
many	O
of	O
the	O
company	O
's	O
mobile	O
devices	O
,	O
including	O
the	O
iPhone	B-Device
;	O
the	O
term	O
also	O
includes	O
the	O
system	B-Application
software	I-Application
for	O
iPads	B-Device
predating	O
iPadOS	B-Operating_System
—	O
which	O
was	O
introduced	O
in	O
2019	O
—	O
as	O
well	O
as	O
on	O
the	B-Device
iPod	I-Device
Touch	O
devices	O
—	O
which	O
were	O
discontinued	O
in	O
mid-2022	O
.	O
</s>
<s>
It	O
is	O
the	O
world	O
's	O
second-most	O
widely	O
installed	O
mobile	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
,	O
after	O
Android	B-Application
.	O
</s>
<s>
It	O
is	O
the	O
basis	O
for	O
three	O
other	O
operating	O
systems	O
made	O
by	O
Apple	O
:	O
iPadOS	B-Operating_System
,	O
tvOS	B-Operating_System
,	O
and	O
watchOS	B-Device
.	O
</s>
<s>
It	O
is	O
proprietary	B-Application
software	I-Application
,	O
although	O
some	O
parts	O
of	O
it	O
are	O
open	B-License
source	I-License
under	O
the	O
Apple	B-License
Public	I-License
Source	I-License
License	I-License
and	O
other	O
licenses	O
.	O
</s>
<s>
Unveiled	O
in	O
2007	O
for	O
the	O
first-generation	B-Operating_System
iPhone	I-Operating_System
,	O
iOS	B-Operating_System
has	O
since	O
been	O
extended	O
to	O
support	O
other	O
Apple	B-Operating_System
devices	I-Operating_System
such	O
as	O
the	B-Device
iPod	I-Device
Touch	O
(	O
September	O
2007	O
)	O
and	O
the	O
iPad	B-Device
(	O
introduced	O
:	O
January	O
2010	O
;	O
availability	O
:	O
April	O
2010	O
.	O
)	O
</s>
<s>
,	O
Apple	B-Application
's	I-Application
App	I-Application
Store	I-Application
contains	O
more	O
than	O
2.1million	O
iOS	B-Application
applications	I-Application
,	O
1million	O
of	O
which	O
are	O
native	O
for	O
iPads	B-Device
.	O
</s>
<s>
These	O
mobile	B-Application
apps	I-Application
have	O
collectively	O
been	O
downloaded	O
more	O
than	O
130billion	O
times	O
.	O
</s>
<s>
Major	O
versions	O
of	O
iOS	B-Operating_System
are	O
released	O
annually	O
.	O
</s>
<s>
The	O
current	O
stable	O
version	O
,	O
iOS	B-Operating_System
16	I-Operating_System
,	O
was	O
released	O
to	O
the	O
public	O
on	O
September	O
12	B-Operating_System
,	O
2022	O
.	O
</s>
<s>
In	O
2005	O
,	O
when	O
Steve	O
Jobs	O
began	O
planning	O
the	O
iPhone	B-Device
,	O
he	O
had	O
a	O
choice	O
to	O
either	O
"	O
shrink	O
the	O
Mac	B-Device
,	O
which	O
would	O
be	O
an	O
epic	O
feat	O
of	O
engineering	O
,	O
or	O
enlarge	O
the	B-Device
iPod	I-Device
"	O
.	O
</s>
<s>
Jobs	O
favored	O
the	O
former	O
approach	O
but	O
pitted	O
the	O
Macintosh	B-Device
and	O
iPod	B-Device
teams	O
,	O
led	O
by	O
Scott	O
Forstall	O
and	O
Tony	O
Fadell	O
,	O
respectively	O
,	O
against	O
each	O
other	O
in	O
an	O
internal	O
competition	O
,	O
with	O
Forstall	O
winning	O
by	O
creating	O
the	O
iPhone	B-Operating_System
OS	I-Operating_System
.	O
</s>
<s>
The	O
decision	O
enabled	O
the	O
success	O
of	O
the	O
iPhone	B-Device
as	O
a	O
platform	O
for	O
third-party	O
developers	O
:	O
using	O
a	O
well-known	O
desktop	B-Application
operating	O
system	O
as	O
its	O
basis	O
allowed	O
the	O
many	O
third-party	O
Mac	B-Device
developers	O
to	O
write	O
software	O
for	O
the	O
iPhone	B-Device
with	O
minimal	O
retraining	O
.	O
</s>
<s>
Forstall	O
was	O
also	O
responsible	O
for	O
creating	O
a	O
software	B-Application
development	I-Application
kit	I-Application
for	O
programmers	O
to	O
build	O
iPhone	B-Application
apps	I-Application
,	O
as	O
well	O
as	O
an	O
App	B-Application
Store	I-Application
within	O
iTunes	B-Operating_System
.	O
</s>
<s>
The	O
operating	O
system	O
was	O
unveiled	O
with	O
the	O
iPhone	B-Device
at	O
the	O
Macworld	O
Conference	O
&	O
Expo	O
on	O
January	O
9	O
,	O
2007	O
,	O
and	O
released	O
in	O
June	O
of	O
that	O
year	O
.	O
</s>
<s>
At	O
the	O
time	O
of	O
its	O
unveiling	O
in	O
January	O
,	O
Steve	O
Jobs	O
claimed	O
:	O
"	O
iPhone	B-Device
runs	O
OS	O
X	B-Operating_System
"	O
and	O
runs	O
"	O
desktop	B-Application
class	O
applications	O
"	O
,	O
but	O
at	O
the	O
time	O
of	O
the	O
iPhone	B-Device
's	O
release	O
,	O
the	O
operating	O
system	O
was	O
renamed	O
"	O
iPhone	B-Operating_System
OS	I-Operating_System
"	O
.	O
</s>
<s>
Jobs	O
 '	O
reasoning	O
was	O
that	O
developers	O
could	O
build	O
web	B-Application
applications	I-Application
through	O
the	B-Application
Safari	I-Application
web	I-Application
browser	I-Application
that	O
"	O
would	O
behave	O
like	O
native	O
apps	B-Application
on	O
the	O
iPhone	B-Device
"	O
.	O
</s>
<s>
In	O
October	O
2007	O
,	O
Apple	O
announced	O
that	O
a	O
native	O
Software	B-Application
Development	I-Application
Kit	I-Application
(	O
SDK	O
)	O
was	O
under	O
development	O
and	O
that	O
they	O
planned	O
to	O
put	O
it	O
"	O
in	O
developers	O
 '	O
hands	O
in	O
February	O
"	O
.	O
</s>
<s>
On	O
March	O
6	O
,	O
2008	O
,	O
Apple	O
held	O
a	O
press	O
event	O
,	O
announcing	O
the	O
iPhone	B-Operating_System
SDK	I-Operating_System
.	O
</s>
<s>
The	O
iOS	B-Application
App	I-Application
Store	I-Application
was	O
opened	O
on	O
July	O
10	O
,	O
2008	O
,	O
with	O
an	O
initial	O
500	O
applications	O
available	O
.	O
</s>
<s>
This	O
quickly	O
grew	O
to	O
3,000	O
in	O
September	O
2008	O
,	O
15,000	O
in	O
January	O
2009	O
,	O
50,000	O
in	O
June	O
2009	O
,	O
100,000	O
in	O
November	O
2009	O
,	O
250,000	O
in	O
August	O
2010	O
,	O
650,000	O
in	O
July	O
2012	O
,	O
1million	O
in	O
October	O
2013	O
,	O
2million	O
in	O
June	O
2016	O
,	O
and	O
2.2million	O
in	O
January	O
2017	O
.	O
,	O
1million	O
apps	B-Application
are	O
natively	O
compatible	O
with	O
the	O
iPad	B-Device
tablet	B-Device
computer	I-Device
.	O
</s>
<s>
These	O
apps	B-Application
have	O
collectively	O
been	O
downloaded	O
more	O
than	O
130billion	O
times	O
.	O
</s>
<s>
App	O
intelligence	O
firm	O
Sensor	O
Tower	O
estimated	O
that	O
the	O
App	B-Application
Store	I-Application
would	O
reach	O
5million	O
apps	B-Application
by	O
2020	O
.	O
</s>
<s>
In	O
September	O
2007	O
,	O
Apple	O
announced	O
the	B-Device
iPod	I-Device
Touch	O
,	O
a	O
redesigned	O
iPod	B-Device
based	O
on	O
the	O
iPhone	B-Device
form	O
factor	O
.	O
</s>
<s>
On	O
January	O
27	O
,	O
2010	O
,	O
Apple	O
introduced	O
their	O
much-anticipated	O
media	O
tablet	B-Device
,	O
the	O
iPad	B-Device
,	O
featuring	O
a	O
larger	O
screen	O
than	O
the	O
iPhone	B-Device
and	O
iPod	B-Operating_System
Touch	I-Operating_System
,	O
and	O
designed	O
for	O
web	O
browsing	O
,	O
media	O
consumption	O
,	O
and	O
reading	O
,	O
and	O
offering	O
multi-touch	B-Application
interaction	O
with	O
multimedia	O
formats	O
including	O
newspapers	O
,	O
e-books	O
,	O
photos	O
,	O
videos	O
,	O
music	O
,	O
word	O
processing	O
documents	O
,	O
video	O
games	O
,	O
and	O
most	O
existing	O
iPhone	B-Application
apps	I-Application
using	O
a	O
screen	O
.	O
</s>
<s>
It	O
also	O
includes	O
a	O
mobile	O
version	O
of	O
Safari	B-Application
for	O
web	O
browsing	O
,	O
as	O
well	O
as	O
access	O
to	O
the	O
App	B-Application
Store	I-Application
,	O
iTunes	B-Operating_System
Library	O
,	O
iBookstore	O
,	O
Contacts	O
,	O
and	O
Notes	O
.	O
</s>
<s>
Content	O
is	O
downloadable	O
via	O
Wi-Fi	O
and	O
optional	O
3G	B-Architecture
service	O
or	O
synced	O
through	O
the	O
user	O
's	O
computer	O
.	O
</s>
<s>
AT&T	O
was	O
initially	O
the	O
sole	O
U.S.	O
provider	O
of	O
3G	B-Architecture
wireless	I-Architecture
access	O
for	O
the	O
iPad	B-Device
.	O
</s>
<s>
In	O
June	O
2010	O
,	O
Apple	O
rebranded	O
iPhone	B-Operating_System
OS	I-Operating_System
as	O
"	O
iOS	B-Operating_System
"	O
.	O
</s>
<s>
The	O
trademark	O
"	O
IOS	B-Operating_System
"	O
had	O
been	O
used	O
by	O
Cisco	O
for	O
over	O
a	O
decade	O
for	O
its	O
operating	O
system	O
,	O
IOS	B-Operating_System
,	O
used	O
on	O
its	O
routers	O
.	O
</s>
<s>
To	O
avoid	O
any	O
potential	O
lawsuit	O
,	O
Apple	O
licensed	O
the	O
"	O
IOS	B-Operating_System
"	O
trademark	O
from	O
Cisco	O
.	O
</s>
<s>
The	O
Apple	B-Device
Watch	I-Device
smartwatch	B-Application
was	O
announced	O
by	O
Tim	O
Cook	O
on	O
September	O
9	O
,	O
2014	O
,	O
being	O
introduced	O
as	O
a	O
product	O
with	O
health	O
and	O
fitness-tracking	O
.	O
</s>
<s>
It	O
uses	O
watchOS	B-Device
as	O
its	O
operating	O
system	O
;	O
watchOS	B-Device
is	O
based	O
on	O
iOS	B-Operating_System
,	O
with	O
new	O
features	O
created	O
specially	O
for	O
the	O
Apple	B-Device
Watch	I-Device
such	O
as	O
an	O
activity	O
tracking	O
app	O
.	O
</s>
<s>
In	O
October	O
2016	O
,	O
Apple	O
opened	O
its	O
first	O
iOS	B-Operating_System
Developer	O
Academy	O
in	O
Naples	O
inside	O
University	O
of	O
Naples	O
Federico	O
II	O
's	O
new	O
campus	O
.	O
</s>
<s>
At	O
the	O
academy	O
there	O
are	O
also	O
issues	O
of	O
business	O
administration	O
(	O
business	O
planning	O
and	O
business	O
management	O
with	O
a	O
focus	O
on	O
digital	O
opportunities	O
)	O
and	O
there	O
is	O
a	O
path	O
dedicated	O
to	O
the	O
design	O
of	O
graphical	B-Application
interfaces	I-Application
.	O
</s>
<s>
As	O
of	O
2020	O
,	O
the	O
academy	O
graduated	O
almost	O
a	O
thousand	O
students	O
from	O
all	O
over	O
the	O
world	O
,	O
who	O
have	O
worked	O
on	O
400	O
app	O
ideas	O
and	O
have	O
already	O
published	O
about	O
50	O
apps	B-Application
on	O
the	O
iOS	B-Application
App	I-Application
Store	I-Application
.	O
</s>
<s>
35	O
of	O
these	O
have	O
been	O
selected	O
to	O
attend	O
the	O
Worldwide	O
Developer	O
Conference	O
,	O
the	O
annual	O
Apple	B-Operating_System
Developer	I-Operating_System
Conference	O
held	O
annually	O
in	O
California	O
in	O
early	O
June	O
.	O
</s>
<s>
On	O
June	O
3	O
,	O
2019	O
,	O
iPadOS	B-Operating_System
,	O
the	O
branded	O
version	O
of	O
iOS	B-Operating_System
for	O
iPad	B-Device
,	O
was	O
announced	O
at	O
the	O
2019	O
WWDC	O
;	O
it	O
was	O
launched	O
on	O
September	O
25	O
,	O
2019	O
.	O
</s>
<s>
The	O
iOS	B-Operating_System
user	B-Application
interface	I-Application
is	O
based	O
upon	O
direct	O
manipulation	O
,	O
using	O
multi-touch	B-Application
gestures	O
such	O
as	O
swipe	O
,	O
tap	O
,	O
pinch	O
,	O
and	O
reverse	O
pinch	O
.	O
</s>
<s>
Internal	O
accelerometers	O
are	O
used	O
by	O
some	O
applications	O
to	O
respond	O
to	O
shaking	O
the	O
device	O
(	O
one	O
common	O
result	O
is	O
the	O
undo	B-Application
command	I-Application
)	O
or	O
rotating	O
it	O
in	O
three	O
dimensions	O
(	O
one	O
common	O
result	O
is	O
switching	O
between	O
portrait	O
and	O
landscape	O
mode	O
)	O
.	O
</s>
<s>
Various	O
accessibility	O
described	O
in	O
functions	O
enable	O
users	O
with	O
vision	O
and	O
hearing	O
disabilities	O
to	O
properly	O
use	O
iOS	B-Operating_System
.	O
</s>
<s>
iOS	B-Operating_System
devices	I-Operating_System
boot	B-Operating_System
to	O
the	O
homescreen	O
,	O
the	O
primary	O
navigation	O
and	O
information	O
"	O
hub	O
"	O
on	O
iOS	B-Operating_System
devices	I-Operating_System
,	O
analogous	O
to	O
the	O
desktop	B-Application
found	O
on	O
personal	O
computers	O
.	O
</s>
<s>
iOS	B-Operating_System
homescreens	O
are	O
typically	O
made	O
up	O
of	O
app	O
icons	O
and	O
widgets	B-Application
;	O
app	O
icons	O
launch	O
the	O
associated	O
app	O
,	O
whereas	O
widgets	B-Application
display	O
live	O
,	O
auto-updating	O
content	O
,	O
such	O
as	O
a	O
weather	O
forecast	O
,	O
the	O
user	O
's	O
email	O
inbox	O
,	O
or	O
a	O
news	O
ticker	O
directly	O
on	O
the	O
homescreen	O
.	O
</s>
<s>
The	O
status	O
bar	O
itself	O
contains	O
two	O
elements	O
,	O
the	O
Control	B-Operating_System
Center	I-Operating_System
and	O
the	O
Notification	B-Operating_System
Center	I-Operating_System
.	O
</s>
<s>
The	O
Control	B-Operating_System
Center	I-Operating_System
can	O
be	O
"	O
pulled	O
"	O
down	O
from	O
the	O
top	O
right	O
of	O
the	O
notch	O
,	O
on	O
the	O
new	O
iPhones	B-Device
,	O
giving	O
access	O
to	O
various	O
toggles	O
to	O
manage	O
the	O
device	O
more	O
quickly	O
without	O
having	O
to	O
open	O
the	O
Settings	O
.	O
</s>
<s>
Instead	O
,	O
scrolling	O
from	O
the	O
top	O
left	O
to	O
the	O
bottom	O
will	O
open	O
the	O
Notification	B-Operating_System
Center	I-Operating_System
,	O
which	O
in	O
the	O
latest	O
versions	O
of	O
iOS	B-Operating_System
is	O
very	O
similar	O
to	O
the	O
lockscreen	O
.	O
</s>
<s>
It	O
displays	O
notifications	O
in	O
chronological	O
order	O
and	O
groups	O
them	O
by	O
application	B-Application
.	O
</s>
<s>
From	O
the	O
notifications	O
of	O
some	O
apps	B-Application
it	O
is	O
possible	O
to	O
interact	O
directly	O
,	O
for	O
example	O
by	O
replying	O
a	O
message	O
directly	O
from	O
it	O
.	O
</s>
<s>
Notifications	O
are	O
sent	O
in	O
two	O
modes	O
,	O
the	O
important	O
notifications	O
that	O
are	O
displayed	O
on	O
the	O
lock	O
screen	O
and	O
signaled	O
by	O
a	O
distinctive	O
sound	O
,	O
accompanied	O
by	O
a	O
warning	O
banner	O
and	O
the	O
app	O
badge	O
icon	O
,	O
and	O
the	O
secondary	O
mode	O
where	O
they	O
are	O
displayed	O
in	O
the	O
Notification	B-Operating_System
Center	I-Operating_System
,	O
but	O
they	O
are	O
not	O
shown	O
on	O
the	O
lock	O
screen	O
,	O
nor	O
are	O
they	O
indicated	O
by	O
warning	O
banners	O
,	O
badge	O
icons	O
or	O
sounds	O
.	O
</s>
<s>
On	O
earlier	O
iPhones	B-Device
with	O
home	O
button	O
,	O
screenshots	B-Application
can	O
be	O
created	O
with	O
the	O
simultaneous	O
press	O
of	O
the	O
home	O
and	O
power	O
buttons	O
.	O
</s>
<s>
In	O
comparison	O
to	O
Android	B-Application
OS	I-Application
,	O
which	O
requires	O
the	O
buttons	O
to	O
be	O
held	O
down	O
,	O
a	O
short	O
press	O
does	O
suffice	O
on	O
iOS	B-Operating_System
.	O
</s>
<s>
On	O
the	O
more	O
recent	O
iPhones	B-Device
which	O
lack	O
a	O
physical	O
home	O
button	O
,	O
screenshots	B-Application
are	O
captured	O
using	O
the	O
volume-up	O
and	O
power	O
buttons	O
instead	O
.	O
</s>
<s>
The	O
camera	O
application	B-Application
used	O
a	O
skeuomorphic	O
closing	O
camera	O
shutter	O
animation	O
prior	O
to	O
iOS	B-Operating_System
7	I-Operating_System
.	O
</s>
<s>
Notable	O
additions	O
over	O
time	O
include	O
HDR	O
photography	O
and	O
the	O
option	O
to	O
save	O
both	O
normal	O
and	O
high	O
dynamic	O
range	O
photographs	O
simultaneously	O
where	O
the	O
former	O
prevents	O
ghosting	O
effects	O
from	O
moving	O
objects	O
(	O
since	O
iPhone	B-Operating_System
5	I-Operating_System
,	O
iOS	B-Operating_System
6	I-Operating_System
)	O
,	O
automatic	O
HDR	O
adjustment	O
(	O
iOS	O
7.1	O
)	O
,	O
"	O
live	O
photo	O
"	O
with	O
short	O
video	O
bundled	O
to	O
each	O
photo	O
if	O
enabled	O
(	O
iPhone	B-Operating_System
6s	I-Operating_System
,	O
iOS	B-Operating_System
9	I-Operating_System
)	O
,	O
and	O
a	O
digital	B-Algorithm
zoom	I-Algorithm
shortcut	O
(	O
iPhone	B-Application
7	I-Application
Plus	I-Application
,	O
iOS	B-Operating_System
10	I-Operating_System
)	O
.	O
</s>
<s>
A	O
new	O
feature	O
in	O
iOS	B-Operating_System
13	I-Operating_System
called	O
"	O
context	O
menus	O
"	O
shows	O
related	O
actions	O
when	O
you	O
touch	O
and	O
hold	O
an	O
item	O
.	O
</s>
<s>
The	O
official	O
font	O
of	O
iOS	B-Operating_System
is	O
San	O
Francisco	O
.	O
</s>
<s>
It	O
is	O
designed	O
for	O
small	O
text	O
readability	O
,	O
and	O
is	O
used	O
throughout	O
the	O
operating	O
system	O
,	O
including	O
third-party	O
apps	B-Application
.	O
</s>
<s>
The	O
icons	O
are	O
180x180px	O
in	O
size	O
for	O
iPhones	B-Device
with	O
a	O
larger	O
screen	O
,	O
usually	O
models	O
over	O
6	O
inches	O
,	O
including	O
iPhone	B-Operating_System
11	I-Operating_System
Pro	I-Operating_System
and	O
iPhone	B-Operating_System
8	I-Operating_System
Plus	I-Operating_System
,	O
while	O
it	O
's	O
120x120px	O
on	O
iPhones	B-Device
with	O
smaller	O
displays	O
.	O
</s>
<s>
iOS	B-Operating_System
devices	I-Operating_System
come	O
with	O
preinstalled	B-Operating_System
apps	I-Operating_System
developed	O
by	O
Apple	O
including	O
Mail	O
,	O
Maps	O
,	O
TV	O
,	O
Music	O
,	O
FaceTime	O
,	O
Wallet	O
,	O
Health	O
,	O
and	O
many	O
more	O
.	O
</s>
<s>
Applications	O
(	O
"	O
apps	B-Application
"	O
)	O
are	O
the	O
most	O
general	O
form	O
of	O
application	B-Application
software	I-Application
that	O
can	O
be	O
installed	O
on	O
iOS	B-Operating_System
.	O
</s>
<s>
They	O
are	O
downloaded	O
from	O
the	O
official	O
catalog	O
of	O
the	O
App	B-Application
Store	I-Application
digital	O
store	O
,	O
where	O
apps	B-Application
are	O
subjected	O
to	O
security	O
checks	O
before	O
being	O
made	O
available	O
to	O
users	O
.	O
</s>
<s>
In	O
June	O
2017	O
,	O
Apple	O
updated	O
its	O
guidelines	O
to	O
specify	O
that	O
app	O
developers	O
will	O
no	O
longer	O
have	O
the	O
ability	O
to	O
use	O
custom	O
prompts	O
for	O
encouraging	O
users	O
to	O
leave	O
reviews	O
for	O
their	O
apps	B-Application
.	O
</s>
<s>
IOS	B-Application
applications	I-Application
can	O
also	O
be	O
installed	O
directly	O
from	O
an	O
IPA	O
file	O
provided	O
by	O
the	O
software	O
distributor	O
,	O
via	O
unofficial	O
ways	O
.	O
</s>
<s>
They	O
are	O
written	O
using	O
iOS	B-Operating_System
Software	I-Operating_System
Development	I-Operating_System
Kit	I-Operating_System
(	O
SDK	O
)	O
and	O
,	O
often	O
,	O
combined	O
with	O
Xcode	B-Operating_System
,	O
using	O
officially	O
supported	O
programming	O
languages	O
,	O
including	O
Swift	B-Application
and	O
Objective-C	B-Language
.	O
Other	O
companies	O
have	O
also	O
created	O
tools	O
that	O
allow	O
for	O
the	O
development	O
of	O
native	O
iOS	B-Application
apps	I-Application
using	O
their	O
respective	O
programming	O
languages	O
.	O
</s>
<s>
Applications	O
for	O
iOS	B-Operating_System
are	O
mostly	O
built	O
using	O
components	O
of	O
UIKit	B-Operating_System
,	O
a	O
programming	O
framework	B-Architecture
.	O
</s>
<s>
Elements	O
automatically	O
update	O
along	O
with	O
iOS	B-Operating_System
updates	O
,	O
automatically	O
including	O
new	O
interface	O
rules	O
.	O
</s>
<s>
UIKit	B-Operating_System
elements	O
are	O
very	O
adaptable	O
,	O
this	O
allows	O
developers	O
to	O
design	O
a	O
single	O
app	O
that	O
looks	O
the	O
same	O
on	O
any	O
iOS	B-Operating_System
device	I-Operating_System
.	O
</s>
<s>
In	O
addition	O
to	O
defining	O
the	O
iOS	B-Operating_System
interface	O
,	O
UIKit	B-Operating_System
defines	O
the	O
functionality	O
of	O
the	O
application	B-Application
.	O
</s>
<s>
At	O
first	O
,	O
Apple	O
did	O
not	O
intend	O
to	O
release	O
an	O
SDK	O
to	O
developers	O
,	O
because	O
they	O
did	O
not	O
want	O
third-party	O
apps	B-Application
to	O
be	O
developed	O
for	O
iOS	B-Operating_System
,	O
building	O
web	B-Application
apps	I-Application
instead	O
.	O
</s>
<s>
The	O
SDK	O
includes	O
an	O
inclusive	O
set	O
of	O
development	O
tools	O
,	O
including	O
an	O
audio	O
mixer	O
and	O
an	O
iPhone	B-Operating_System
simulator	I-Operating_System
.	O
</s>
<s>
It	O
is	O
a	O
free	O
download	O
for	O
Mac	B-Device
users	O
.	O
</s>
<s>
It	O
is	O
not	O
available	O
for	O
Microsoft	B-Application
Windows	I-Application
PCs	O
.	O
</s>
<s>
To	O
test	O
the	O
application	B-Application
,	O
get	O
technical	O
support	O
,	O
and	O
distribute	O
applications	O
through	O
App	B-Application
Store	I-Application
,	O
developers	O
are	O
required	O
to	O
subscribe	O
to	O
the	O
Apple	B-Operating_System
Developer	I-Operating_System
Program	I-Operating_System
.	O
</s>
<s>
Over	O
the	O
years	O
,	O
the	O
Apple	O
Store	O
apps	B-Application
surpassed	O
multiple	O
major	O
milestones	O
,	O
including	O
50	O
,	O
000	O
,	O
100	O
,	O
000	O
,	O
250	O
,	O
000	O
,	O
500	O
,	O
000	O
,	O
1million	O
,	O
and	O
2million	O
apps	B-Application
.	O
</s>
<s>
The	O
billionth	O
application	B-Application
was	O
installed	O
on	O
April	O
24	O
,	O
2009	O
.	O
</s>
<s>
The	O
home	O
screen	O
,	O
rendered	O
by	O
SpringBoard	O
,	O
displays	O
application	B-Application
icons	O
and	O
a	O
dock	O
at	O
the	O
bottom	O
where	O
users	O
can	O
pin	O
their	O
most	O
frequently	O
used	O
apps	B-Application
.	O
</s>
<s>
Before	O
iOS	B-Operating_System
4	I-Operating_System
on	O
the	O
iPhone	B-Operating_System
3GS	I-Operating_System
(	O
or	O
later	O
)	O
,	O
the	O
screen	O
's	O
background	O
could	O
be	O
customized	O
only	O
through	O
jailbreaking	B-Application
,	O
but	O
can	O
now	O
be	O
changed	O
out-of-the-box	O
.	O
</s>
<s>
The	O
rest	O
of	O
the	O
screen	O
is	O
devoted	O
to	O
the	O
current	O
application	B-Application
.	O
</s>
<s>
In	O
iPhone	B-Operating_System
OS	I-Operating_System
3	I-Operating_System
,	O
Spotlight	B-Application
was	O
introduced	O
,	O
allowing	O
users	O
to	O
search	O
media	O
,	O
apps	B-Application
,	O
emails	O
,	O
contacts	O
,	O
messages	O
,	O
reminders	O
,	O
calendar	O
events	O
,	O
and	O
similar	O
content	O
.	O
</s>
<s>
In	O
iOS	B-Operating_System
7	I-Operating_System
and	O
later	O
,	O
Spotlight	B-Application
is	O
accessed	O
by	O
pulling	O
down	O
anywhere	O
on	O
the	O
home	O
screen	O
(	O
except	O
for	O
the	O
top	O
and	O
bottom	O
edges	O
that	O
open	O
Notification	B-Operating_System
Center	I-Operating_System
and	O
Control	B-Operating_System
Center	I-Operating_System
)	O
.	O
</s>
<s>
In	O
iOS	B-Operating_System
9	I-Operating_System
,	O
there	O
are	O
two	O
ways	O
to	O
access	O
Spotlight	B-Application
.	O
</s>
<s>
As	O
with	O
iOS	B-Operating_System
7	I-Operating_System
and	O
8	O
,	O
pulling	O
down	O
on	O
any	O
homescreen	O
will	O
show	O
Spotlight	B-Application
.	O
</s>
<s>
However	O
,	O
it	O
can	O
also	O
be	O
accessed	O
as	O
it	O
was	O
in	O
iOS	B-Operating_System
versions	O
3	O
through	O
6	O
.	O
</s>
<s>
This	O
endows	O
Spotlight	B-Application
with	O
Siri	O
suggestions	O
,	O
which	O
include	O
app	O
suggestions	O
,	O
contact	O
suggestions	O
and	O
news	O
.	O
</s>
<s>
In	O
iOS	B-Operating_System
10	I-Operating_System
,	O
Spotlight	B-Application
is	O
at	O
the	O
top	O
of	O
the	O
now-dedicated	O
"	O
Today	O
"	O
panel	O
.	O
</s>
<s>
Since	O
iOS	B-Operating_System
3.2	I-Operating_System
,	O
users	O
are	O
able	O
to	O
set	O
a	O
background	O
image	O
for	O
the	O
Home	O
Screen	O
.	O
</s>
<s>
This	O
feature	O
is	O
only	O
available	O
on	O
third-generation	O
devices	O
—	O
iPhone	B-Operating_System
3GS	I-Operating_System
,	O
third-generation	O
iPod	B-Operating_System
Touch	I-Operating_System
(	O
iOS	B-Operating_System
4.0	I-Operating_System
or	O
newer	O
)	O
,	O
and	O
all	O
iPad	B-Device
models	O
(	O
since	O
iOS	B-Operating_System
3.2	I-Operating_System
)	O
—	O
or	O
newer	O
.	O
</s>
<s>
iOS	B-Operating_System
7	I-Operating_System
introduced	O
a	O
parallax	O
effect	O
on	O
the	O
Home	O
Screen	O
,	O
which	O
shifts	O
the	O
device	O
's	O
wallpaper	O
and	O
icons	O
in	O
response	O
to	O
the	O
movement	O
of	O
the	O
device	O
,	O
creating	O
a	O
3D	O
effect	O
and	O
an	O
illusion	O
of	O
floating	O
icons	O
.	O
</s>
<s>
This	O
effect	O
is	O
also	O
visible	O
in	O
the	O
tab	O
view	O
of	O
Mail	O
and	O
Safari	B-Application
.	O
</s>
<s>
iOS	B-Operating_System
originally	O
used	O
Helvetica	O
as	O
the	O
system	O
font	O
.	O
</s>
<s>
Apple	O
switched	O
to	O
Helvetica	O
Neue	O
exclusively	O
for	O
the	O
iPhone	B-Operating_System
4	I-Operating_System
and	O
its	O
Retina	B-Operating_System
Display	I-Operating_System
,	O
and	O
retained	O
Helvetica	O
as	O
the	O
system	O
font	O
for	O
older	O
iPhone	B-Device
devices	O
on	O
iOS	B-Operating_System
4	I-Operating_System
.	O
</s>
<s>
With	O
iOS	B-Operating_System
7	I-Operating_System
,	O
Apple	O
announced	O
that	O
they	O
would	O
change	O
the	O
system	O
font	O
to	O
Helvetica	O
Neue	O
Light	O
,	O
a	O
decision	O
that	O
sparked	O
criticism	O
for	O
inappropriate	O
usage	O
of	O
a	O
light	O
,	O
thin	O
typeface	O
for	O
low-resolution	O
mobile	O
screens	O
.	O
</s>
<s>
The	O
release	O
of	O
iOS	B-Operating_System
7	I-Operating_System
also	O
introduced	O
the	O
ability	O
to	O
scale	O
text	O
or	O
apply	O
other	O
forms	O
of	O
text	O
accessibility	O
changes	O
through	O
Settings	O
.	O
</s>
<s>
With	O
iOS	B-Operating_System
9	I-Operating_System
,	O
Apple	O
changed	O
the	O
font	O
to	O
San	O
Francisco	O
,	O
an	O
Apple-designed	O
font	O
aimed	O
at	O
maximum	O
legibility	O
and	O
font	O
consistency	O
across	O
its	O
product	O
lineup	O
.	O
</s>
<s>
iOS	B-Operating_System
4	I-Operating_System
introduced	O
folders	O
,	O
which	O
can	O
be	O
created	O
by	O
dragging	O
an	O
application	B-Application
on	O
top	O
of	O
another	O
,	O
and	O
from	O
then	O
on	O
,	O
more	O
items	O
can	O
be	O
added	O
to	O
the	O
folder	O
using	O
the	O
same	O
procedure	O
.	O
</s>
<s>
When	O
apps	B-Application
inside	O
folders	O
receive	O
notification	O
badges	O
,	O
the	O
individual	O
numbers	O
of	O
notifications	O
are	O
added	O
up	O
and	O
the	O
total	O
number	O
is	O
displayed	O
as	O
a	O
notification	O
badge	O
on	O
the	O
folder	O
itself	O
.	O
</s>
<s>
Originally	O
,	O
folders	O
on	O
an	O
iPhone	B-Device
could	O
include	O
up	O
to	O
12	B-Operating_System
apps	B-Application
,	O
while	O
folders	O
on	O
iPad	B-Device
could	O
include	O
20	O
.	O
</s>
<s>
With	O
increasing	O
display	O
sizes	O
on	O
newer	O
iPhone	B-Device
hardware	O
,	O
iOS	B-Operating_System
7	I-Operating_System
updated	O
the	O
folders	O
with	O
pages	O
similar	O
to	O
the	O
home	O
screen	O
layout	O
,	O
allowing	O
for	O
a	O
significant	O
expansion	O
of	O
folder	O
functionality	O
.	O
</s>
<s>
Each	O
page	O
of	O
a	O
folder	O
can	O
contain	O
up	O
to	O
nine	O
apps	B-Application
,	O
and	O
there	O
can	O
be	O
15	O
pages	O
in	O
total	O
,	O
allowing	O
for	O
a	O
total	O
of	O
135	O
apps	B-Application
in	O
a	O
single	O
folder	O
.	O
</s>
<s>
In	O
iOS	B-Operating_System
9	I-Operating_System
,	O
Apple	O
updated	O
folder	O
sizes	O
for	O
iPad	B-Device
hardware	O
,	O
allowing	O
for	O
16	O
apps	B-Application
per	O
page	O
,	O
still	O
at	O
15	O
pages	O
maximum	O
,	O
increasing	O
the	O
total	O
to	O
240	O
apps	B-Application
.	O
</s>
<s>
Before	O
iOS	B-Operating_System
5	I-Operating_System
,	O
notifications	O
were	O
delivered	O
in	O
a	O
modal	O
window	O
and	O
could	O
n't	O
be	O
viewed	O
after	O
being	O
dismissed	O
.	O
</s>
<s>
In	O
iOS	B-Operating_System
5	I-Operating_System
,	O
Apple	O
introduced	O
Notification	B-Operating_System
Center	I-Operating_System
,	O
which	O
allows	O
users	O
to	O
view	O
a	O
history	O
of	O
notifications	O
.	O
</s>
<s>
If	O
a	O
user	O
taps	O
a	O
received	O
notification	O
,	O
the	O
application	B-Application
that	O
sent	O
the	O
notification	O
will	O
be	O
opened	O
.	O
</s>
<s>
Users	O
can	O
also	O
choose	O
to	O
view	O
notifications	O
in	O
modal	O
alert	O
windows	O
by	O
adjusting	O
the	O
application	B-Application
's	O
notification	O
settings	O
.	O
</s>
<s>
Introduced	O
with	O
iOS	B-Operating_System
8	O
,	O
widgets	B-Application
are	O
now	O
accessible	O
through	O
the	O
Notification	B-Operating_System
Center	I-Operating_System
,	O
defined	O
by	O
3rd	O
parties	O
.	O
</s>
<s>
When	O
an	O
app	O
sends	O
a	O
notification	O
while	O
closed	B-Application
,	O
a	O
red	O
badge	O
appears	O
on	O
its	O
icon	O
.	O
</s>
<s>
iOS	B-Operating_System
offers	O
various	O
accessibility	O
features	O
to	O
help	O
users	O
with	O
vision	O
and	O
hearing	O
disabilities	O
.	O
</s>
<s>
One	O
major	O
feature	O
,	O
VoiceOver	B-Operating_System
,	O
provides	O
a	O
voice	O
reading	O
information	O
on	O
the	O
screen	O
,	O
including	O
contextual	O
buttons	O
,	O
icons	O
,	O
links	O
and	O
other	O
user	B-Application
interface	I-Application
elements	O
,	O
and	O
allows	O
the	O
user	O
to	O
navigate	O
the	O
operating	O
system	O
through	O
gestures	O
.	O
</s>
<s>
Any	O
apps	B-Application
with	O
default	O
controls	O
and	O
developed	O
with	O
a	O
UIKit	B-Operating_System
framework	B-Architecture
gets	O
VoiceOver	B-Operating_System
functionality	O
built	O
in	O
.	O
</s>
<s>
One	O
example	O
includes	O
holding	O
up	O
the	O
iPhone	B-Device
to	O
take	O
a	O
photo	O
,	O
with	O
VoiceOver	B-Operating_System
describing	O
the	O
photo	O
scenery	O
.	O
</s>
<s>
As	O
part	O
of	O
a	O
"	O
Made	O
for	O
iPhone	B-Device
"	O
program	O
,	O
introduced	O
with	O
the	O
release	O
of	O
iOS	B-Operating_System
7	I-Operating_System
in	O
2013	O
,	O
Apple	O
has	O
developed	O
technology	O
to	O
use	O
Bluetooth	B-Protocol
and	O
a	O
special	O
technology	O
protocol	O
to	O
let	O
compatible	O
third-party	O
equipment	O
connect	O
with	O
iPhones	B-Device
and	O
iPads	B-Device
for	O
streaming	O
audio	O
directly	O
to	O
a	O
user	O
's	O
ears	O
.	O
</s>
<s>
Additional	O
customization	O
available	O
for	O
Made	O
for	O
iPhone	B-Device
products	O
include	O
battery	O
tracking	O
and	O
adjustable	O
sound	O
settings	O
for	O
different	O
environments	O
.	O
</s>
<s>
Apple	O
made	O
further	O
efforts	O
for	O
accessibility	O
for	O
the	O
release	O
of	O
iOS	B-Operating_System
10	I-Operating_System
in	O
2016	O
,	O
adding	O
a	O
new	O
pronunciation	O
editor	O
to	O
VoiceOver	B-Operating_System
,	O
adding	O
a	O
Magnifier	O
setting	O
to	O
enlarge	O
objects	O
through	O
the	O
device	O
's	O
camera	O
,	O
software	O
TTY	O
support	O
for	O
deaf	O
people	O
to	O
make	O
phone	O
calls	O
from	O
the	O
iPhone	B-Device
,	O
and	O
giving	O
tutorials	O
and	O
guidelines	O
for	O
third-party	O
developers	O
to	O
incorporate	O
proper	O
accessibility	O
functions	O
into	O
their	O
apps	B-Application
.	O
</s>
<s>
In	O
2012	O
,	O
Liat	O
Kornowski	O
from	O
The	O
Atlantic	O
wrote	O
that	O
"	O
the	O
iPhone	B-Device
has	O
turned	O
out	O
to	O
be	O
one	O
of	O
the	O
most	O
revolutionary	O
developments	O
since	O
the	O
invention	O
of	O
Braille	O
"	O
,	O
and	O
in	O
2016	O
,	O
Steven	O
Aquino	O
of	O
TechCrunch	O
described	O
Apple	O
as	O
"	O
leading	O
the	O
way	O
in	O
assistive	O
technology	O
"	O
,	O
with	O
Sarah	O
Herrlinger	O
,	O
Senior	O
Manager	O
for	O
Global	O
Accessibility	O
Policy	O
and	O
Initiatives	O
at	O
Apple	O
,	O
stating	O
that	O
"	O
We	O
see	O
accessibility	O
as	O
a	O
basic	O
human	O
right	O
.	O
</s>
<s>
Criticism	O
has	O
been	O
aimed	O
at	O
iOS	B-Operating_System
depending	O
on	O
both	O
internet	O
connection	O
(	O
either	O
WiFi	O
or	O
through	O
iTunes	B-Operating_System
)	O
and	O
a	O
working	O
SIM	O
card	O
upon	O
first	O
activation	O
.	O
</s>
<s>
This	O
restriction	O
has	O
been	O
loosened	O
in	O
iOS	B-Operating_System
12	B-Operating_System
,	O
which	O
no	O
longer	O
requires	O
the	O
latter	O
.	O
</s>
<s>
Multitasking	B-Operating_System
for	O
iOS	B-Operating_System
was	O
first	O
released	O
in	O
June	O
2010	O
along	O
with	O
the	O
release	O
of	O
iOS	B-Operating_System
4	I-Operating_System
.	O
</s>
<s>
Only	O
certain	O
devices	O
—	O
iPhone	B-Operating_System
4	I-Operating_System
,	O
iPhone	B-Operating_System
3GS	I-Operating_System
,	O
and	O
iPod	B-Operating_System
Touch	I-Operating_System
3rd	O
generation	O
—	O
were	O
able	O
to	O
multitask	O
.	O
</s>
<s>
The	O
iPad	B-Device
did	O
not	O
get	O
multitasking	B-Operating_System
until	O
iOS	O
4.2.1	O
in	O
that	O
November	O
.	O
</s>
<s>
The	O
implementation	O
of	O
multitasking	B-Operating_System
in	O
iOS	B-Operating_System
has	O
been	O
criticized	O
for	O
its	O
approach	O
,	O
which	O
limits	O
the	O
work	O
that	O
applications	O
in	O
the	O
background	O
can	O
perform	O
to	O
a	O
limited	O
function	O
set	O
and	O
requires	O
application	B-Application
developers	O
to	O
add	O
explicit	O
support	O
for	O
it	O
.	O
</s>
<s>
Before	O
iOS	B-Operating_System
4	I-Operating_System
,	O
multitasking	B-Operating_System
was	O
limited	O
to	O
a	O
selection	O
of	O
the	O
applications	O
Apple	O
included	O
on	O
the	O
device	O
.	O
</s>
<s>
Users	O
could	O
however	O
"	O
jailbreak	B-Application
"	O
their	O
device	O
in	O
order	O
to	O
unofficially	O
multitask	O
.	O
</s>
<s>
Starting	O
with	O
iOS	B-Operating_System
4	I-Operating_System
,	O
on	O
third-generation	O
and	O
newer	O
iOS	B-Operating_System
devices	I-Operating_System
,	O
multitasking	B-Operating_System
is	O
supported	O
through	O
seven	O
background	O
APIs	B-Application
:	O
</s>
<s>
In	O
iOS	B-Operating_System
5	I-Operating_System
,	O
three	O
new	O
background	O
APIs	B-Application
were	O
introduced	O
:	O
</s>
<s>
In	O
iOS	B-Operating_System
7	I-Operating_System
,	O
Apple	O
introduced	O
a	O
new	O
multitasking	B-Operating_System
feature	O
,	O
providing	O
all	O
apps	B-Application
with	O
the	O
ability	O
to	O
perform	O
background	O
updates	O
.	O
</s>
<s>
This	O
feature	O
prefers	O
to	O
update	O
the	O
user	O
's	O
most	O
frequently	O
used	O
apps	B-Application
and	O
prefers	O
to	O
use	O
Wi-Fi	O
networks	O
over	O
a	O
cellular	O
network	O
,	O
without	O
markedly	O
reducing	O
the	O
device	O
's	O
battery	O
life	O
.	O
</s>
<s>
In	O
iOS	B-Operating_System
4.0	I-Operating_System
to	O
iOS	O
6.x	O
,	O
double-clicking	O
the	O
home	O
button	O
activates	O
the	O
application	B-Application
switcher	O
.	O
</s>
<s>
Choosing	O
an	O
icon	O
switches	O
to	O
an	O
application	B-Application
.	O
</s>
<s>
With	O
the	O
introduction	O
of	O
iOS	B-Operating_System
7	I-Operating_System
,	O
double-clicking	O
the	O
home	O
button	O
also	O
activates	O
the	O
application	B-Application
switcher	O
.	O
</s>
<s>
However	O
,	O
unlike	O
previous	O
versions	O
it	O
displays	O
screenshots	B-Application
of	O
open	O
applications	O
on	O
top	O
of	O
the	O
icon	O
and	O
horizontal	O
scrolling	O
allows	O
for	O
browsing	O
through	O
previous	O
apps	B-Application
,	O
and	O
it	O
is	O
possible	O
to	O
close	O
applications	O
by	O
dragging	O
them	O
up	O
,	O
similar	O
to	O
how	O
WebOS	B-Operating_System
handled	O
multiple	O
cards	O
.	O
</s>
<s>
With	O
the	O
introduction	O
of	O
iOS	B-Operating_System
9	I-Operating_System
,	O
the	O
application	B-Application
switcher	O
received	O
a	O
significant	O
visual	O
change	O
;	O
while	O
still	O
retaining	O
the	O
card	O
metaphor	O
introduced	O
in	O
iOS	B-Operating_System
7	I-Operating_System
,	O
the	O
application	B-Application
icon	O
is	O
smaller	O
,	O
and	O
appears	O
above	O
the	O
screenshot	B-Application
(	O
which	O
is	O
now	O
larger	O
,	O
due	O
to	O
the	O
removal	O
of	O
"	O
Recent	O
and	O
Favorite	O
Contacts	O
"	O
)	O
,	O
and	O
each	O
application	B-Application
"	O
card	O
"	O
overlaps	O
the	O
other	O
,	O
forming	O
a	O
rolodex	O
effect	O
as	O
the	O
user	O
scrolls	O
.	O
</s>
<s>
Now	O
,	O
instead	O
of	O
the	O
home	O
screen	O
appearing	O
at	O
the	O
leftmost	O
of	O
the	O
application	B-Application
switcher	O
,	O
it	O
appears	O
rightmost	O
.	O
</s>
<s>
In	O
iOS	B-Operating_System
11	I-Operating_System
,	O
the	O
application	B-Application
switcher	O
receives	O
a	O
major	O
redesign	O
.	O
</s>
<s>
In	O
the	O
iPad	B-Device
,	O
the	O
Control	B-Operating_System
Center	I-Operating_System
and	O
app	O
switcher	O
are	O
combined	O
.	O
</s>
<s>
The	O
app	O
switcher	O
in	O
the	O
iPad	B-Device
can	O
also	O
be	O
accessed	O
by	O
swiping	O
up	O
from	O
the	O
bottom	O
.	O
</s>
<s>
In	O
the	O
iPhone	B-Device
,	O
the	O
app	O
switcher	O
cannot	O
be	O
accessed	O
if	O
there	O
are	O
no	O
apps	B-Application
in	O
the	O
RAM	B-Architecture
.	O
</s>
<s>
In	O
iOS	B-Operating_System
4.0	I-Operating_System
to	O
iOS	O
6.x	O
,	O
briefly	O
holding	O
the	O
icons	O
in	O
the	O
application	B-Application
switcher	O
makes	O
them	O
"	O
jiggle	O
"	O
(	O
similarly	O
to	O
the	O
homescreen	O
)	O
and	O
allows	O
the	O
user	O
to	O
force	O
quit	O
the	O
applications	O
by	O
tapping	O
the	O
red	O
minus	O
circle	O
that	O
appears	O
at	O
the	O
corner	O
of	O
the	O
app	O
's	O
icon	O
.	O
</s>
<s>
Clearing	O
applications	O
from	O
multitasking	B-Operating_System
stayed	O
the	O
same	O
from	O
iOS	B-Operating_System
4.0	I-Operating_System
through	O
6.1.6	O
,	O
the	O
last	O
version	O
of	O
iOS	B-Operating_System
6	I-Operating_System
.	O
</s>
<s>
As	O
of	O
iOS	B-Operating_System
7	I-Operating_System
,	O
the	O
process	O
has	O
become	O
faster	O
and	O
easier	O
.	O
</s>
<s>
In	O
iOS	B-Operating_System
7	I-Operating_System
,	O
instead	O
of	O
holding	O
the	O
icons	O
to	O
close	O
them	O
,	O
they	O
are	O
closed	B-Application
by	O
simply	O
swiping	O
them	O
upwards	O
off	O
the	O
screen	O
.	O
</s>
<s>
Up	O
to	O
three	O
apps	B-Application
can	O
be	O
cleared	O
at	O
a	O
time	O
compared	O
to	O
one	O
in	O
versions	O
up	O
to	O
iOS	O
6.1.6	O
.	O
</s>
<s>
Task	O
completion	O
allows	O
apps	B-Application
to	O
continue	O
a	O
certain	O
task	O
after	O
the	O
app	O
has	O
been	O
suspended	O
.	O
</s>
<s>
As	O
of	O
iOS	B-Operating_System
4.0	I-Operating_System
,	O
apps	B-Application
can	O
request	O
up	O
to	O
ten	O
minutes	O
to	O
complete	O
a	O
task	O
in	O
the	O
background	O
.	O
</s>
<s>
if	O
a	O
user	O
starts	O
a	O
download	O
in	O
one	O
application	B-Application
,	O
it	O
wo	O
n't	O
finish	O
if	O
they	O
switch	O
away	O
from	O
the	O
application	B-Application
)	O
.	O
</s>
<s>
Siri	O
(	O
)	O
is	O
an	O
intelligent	B-Protocol
personal	I-Protocol
assistant	I-Protocol
integrated	O
into	O
iOS	B-Operating_System
.	O
</s>
<s>
The	O
assistant	O
uses	O
voice	O
queries	O
and	O
a	O
natural	B-General_Concept
language	I-General_Concept
user	I-General_Concept
interface	I-General_Concept
to	O
answer	O
questions	O
,	O
make	O
recommendations	O
,	O
and	O
perform	O
actions	O
by	O
delegating	O
requests	O
to	O
a	O
set	O
of	O
Internet	O
services	O
.	O
</s>
<s>
Originally	O
released	O
as	O
an	O
app	O
for	O
iOS	B-Operating_System
in	O
February	O
2010	O
,	O
it	O
was	O
acquired	O
by	O
Apple	O
two	O
months	O
later	O
,	O
and	O
then	O
integrated	O
into	O
iPhone	B-Operating_System
4S	I-Operating_System
at	O
its	O
release	O
in	O
October	O
2011	O
.	O
</s>
<s>
At	O
that	O
time	O
,	O
the	O
separate	O
app	O
was	O
also	O
removed	O
from	O
the	O
iOS	B-Application
App	I-Application
Store	I-Application
.	O
</s>
<s>
Siri	O
supports	O
a	O
wide	O
range	O
of	O
user	O
commands	O
,	O
including	O
performing	O
phone	O
actions	O
,	O
checking	O
basic	O
information	O
,	O
scheduling	O
events	O
and	O
reminders	O
,	O
handling	O
device	O
settings	O
,	O
searching	O
the	O
Internet	O
,	O
navigating	O
areas	O
,	O
finding	O
information	O
on	O
entertainment	O
,	O
and	O
is	O
able	O
to	O
engage	O
with	O
iOS-integrated	O
apps	B-Application
.	O
</s>
<s>
With	O
the	O
release	O
of	O
iOS	B-Operating_System
10	I-Operating_System
in	O
2016	O
,	O
Apple	O
opened	O
up	O
limited	O
third-party	O
access	O
to	O
Siri	O
,	O
including	O
third-party	O
messaging	O
apps	B-Application
,	O
as	O
well	O
as	O
payments	O
,	O
ride-sharing	O
,	O
and	O
Internet	O
calling	O
apps	B-Application
.	O
</s>
<s>
With	O
the	O
release	O
of	O
iOS	B-Operating_System
11	I-Operating_System
,	O
Apple	O
updated	O
Siri	O
's	O
voices	O
for	O
more	O
clear	O
,	O
human	O
voices	O
,	O
it	O
now	O
supports	O
follow-up	O
questions	O
and	O
language	O
translation	O
,	O
and	O
additional	O
third-party	O
actions	O
.	O
</s>
<s>
iOS	B-Operating_System
5	I-Operating_System
and	O
above	O
adds	O
support	O
for	O
profile	O
photos	O
.	O
</s>
<s>
Game	O
Center	O
was	O
announced	O
during	O
an	O
iOS	B-Operating_System
4	I-Operating_System
preview	O
event	O
hosted	O
by	O
Apple	O
on	O
April	O
8	O
,	O
2010	O
.	O
</s>
<s>
A	O
preview	O
was	O
released	O
to	O
registered	O
Apple	B-Operating_System
developers	I-Operating_System
in	O
August	O
.	O
</s>
<s>
It	O
was	O
released	O
on	O
September	O
8	O
,	O
2010	O
,	O
with	O
iOS	O
4.1	O
on	O
iPhone	B-Operating_System
4	I-Operating_System
,	O
iPhone	B-Operating_System
3GS	I-Operating_System
,	O
and	O
iPod	B-Operating_System
Touch	I-Operating_System
2nd	O
generation	O
through	O
4th	O
generation	O
.	O
</s>
<s>
Game	O
Center	O
made	O
its	O
public	O
debut	O
on	O
the	O
iPad	B-Device
with	O
iOS	O
4.2.1	O
.	O
</s>
<s>
There	O
is	O
no	O
support	O
for	O
the	O
iPhone	B-Operating_System
3G	I-Operating_System
,	O
original	B-Operating_System
iPhone	I-Operating_System
and	O
the	O
first-generation	B-Device
iPod	I-Device
Touch	I-Device
(	O
the	O
latter	O
two	O
devices	O
did	O
not	O
have	O
Game	O
Center	O
because	O
they	O
did	O
not	O
get	O
iOS	B-Operating_System
4	I-Operating_System
)	O
.	O
</s>
<s>
However	O
,	O
Game	O
Center	O
is	O
unofficially	O
available	O
on	O
the	O
iPhone	B-Operating_System
3G	I-Operating_System
via	O
a	O
hack	O
.	O
</s>
<s>
The	O
main	O
hardware	O
platform	O
for	O
iOS	B-Operating_System
is	O
the	O
ARM	B-Architecture
architecture	I-Architecture
(	O
the	O
ARMv7	O
,	O
ARMv8-A	O
,	O
ARMv8.2-A	O
,	O
ARMv8.3-A	O
)	O
.	O
</s>
<s>
iOS	B-Operating_System
releases	O
before	O
iOS	B-Operating_System
7	I-Operating_System
can	O
only	O
be	O
run	O
on	O
iOS	B-Operating_System
devices	I-Operating_System
with	O
32-bit	O
ARM	B-Architecture
processors	I-Architecture
(	O
ARMv6	O
and	O
ARMv7-A	O
architectures	O
)	O
.	O
</s>
<s>
In	O
2013	O
,	O
iOS	B-Operating_System
7	I-Operating_System
was	O
released	O
with	O
full	O
64-bit	B-Device
support	I-Device
(	O
which	O
includes	O
a	O
native	O
64-bit	B-Device
kernel	B-Operating_System
,	O
libraries	O
,	O
drivers	O
as	O
well	O
as	O
all	O
built-in	O
applications	O
)	O
,	O
after	O
Apple	O
announced	O
that	O
they	O
were	O
switching	O
to	O
64-bit	B-Device
ARMv8-A	O
processors	O
with	O
the	O
introduction	O
of	O
the	O
Apple	O
A7	O
chip	O
.	O
</s>
<s>
64-bit	B-Device
support	I-Device
was	O
also	O
enforced	O
for	O
all	O
apps	B-Application
in	O
the	O
App	B-Application
Store	I-Application
;	O
All	O
new	O
apps	B-Application
submitted	O
to	O
the	O
App	B-Application
Store	I-Application
with	O
a	O
deadline	O
of	O
February	O
2015	O
,	O
and	O
all	O
app	O
updates	O
submitted	O
to	O
the	O
App	B-Application
Store	I-Application
with	O
a	O
deadline	O
of	O
June	O
1	O
,	O
2015	O
.	O
iOS	B-Operating_System
11	I-Operating_System
drops	O
support	O
for	O
all	O
iOS	B-Operating_System
devices	I-Operating_System
with	O
32-bit	O
ARM	B-Architecture
processors	I-Architecture
as	O
well	O
as	O
32-bit	O
applications	O
,	O
making	O
iOS	B-Operating_System
64-bit	B-Device
only	O
.	O
</s>
<s>
iOS	B-Operating_System
has	O
support	O
for	O
many	O
locales	O
.	O
</s>
<s>
+List	O
of	O
locales	O
by	O
iOS	B-Operating_System
versionLanguageEnglish	O
name1.01.1.22.02.1-2.234-678910-1516	O
+English	O
(	O
US	O
)	O
English	O
(	O
US	O
)	O
English	O
(	O
Canada	O
)	O
English	O
(	O
Canada	O
)	O
English	O
(	O
UK	O
)	O
English	O
(	O
UK	O
)	O
English	O
(	O
Ireland	O
)	O
English	O
(	O
Ireland	O
)	O
English	O
(	O
Singapore	O
)	O
English	O
(	O
Singapore	O
)	O
English	O
(	O
South	O
Africa	O
)	O
English	O
(	O
South	O
Africa	O
)	O
English	O
(	O
Australia	O
)	O
English	O
(	O
Australia	O
)	O
English	O
(	O
New	O
Zealand	O
)	O
English	O
(	O
New	O
Zealand	O
)	O
English	O
(	O
India	O
)	O
English	O
(	O
India	O
)	O
简体中文Chinese	O
,	O
Simplified繁體中文	O
（台灣）	O
Chinese	O
,	O
Traditional	O
(	O
Taiwan	O
)	O
繁體中文	O
（香港）	O
Chinese	O
,	O
Traditional	O
(	O
Hong	O
Kong	O
)	O
繁體中文	O
（澳門）	O
Chinese	O
,	O
Traditional	O
(	O
Macau	O
)	O
日本語JapaneseEspañol	O
(	O
España	O
)	O
Spanish	O
(	O
Spain	O
)	O
Español	O
(	O
Latinoamérica	O
)	O
Spanish	O
(	O
Latin	O
America	O
)	O
Español	O
(	O
México	O
)	O
Spanish	O
(	O
Mexico	O
)	O
Español	O
(	O
Argentina	O
)	O
Spanish	O
(	O
Argentina	O
)	O
Español	O
(	O
Bolivia	O
)	O
Spanish	O
(	O
Bolivia	O
)	O
Español	O
(	O
Chile	O
)	O
Spanish	O
(	O
Chile	O
)	O
Español	O
(	O
Colombia	O
)	O
Spanish	O
(	O
Colombia	O
)	O
Español	O
(	O
Costa	O
Rica	O
)	O
Spanish	O
(	O
Costa	O
Rica	O
)	O
Español	O
(	O
Ecuador	O
)	O
Spanish	O
(	O
Ecuador	O
)	O
Español	O
(	O
El	O
Salvador	O
)	O
Spanish	O
(	O
El	O
Salvador	O
)	O
Español	O
(	O
EE	O
.	O
</s>
