<s>
Night	B-Operating_System
Shift	I-Operating_System
is	O
a	O
built	O
in	O
software	O
feature	O
of	O
iOS	B-Application
and	O
macOS	B-Application
.	O
</s>
<s>
It	O
was	O
introduced	O
in	O
2016-2017	O
into	O
iOS	B-Application
in	O
iOS	B-Application
9.3	O
and	O
into	O
macOS	B-Application
in	O
macOS	B-Operating_System
Sierra	I-Operating_System
10.12.4	I-Operating_System
.	O
</s>
<s>
The	O
feature	O
is	O
similar	O
to	O
the	O
functionality	O
f.lux	B-Operating_System
provides	O
.	O
</s>
<s>
The	O
Night	B-Operating_System
Shift	I-Operating_System
feature	O
is	O
compatible	O
with	O
all	O
64-bit	B-Device
iOS	B-Application
devices	O
running	O
on	O
iOS	B-Application
9.3	O
and	O
above	O
and	O
Macs	B-Device
from	O
2012	O
and	O
later	O
running	O
on	O
macOS	B-Operating_System
Sierra	I-Operating_System
10.12.4	I-Operating_System
and	O
above	O
.	O
</s>
<s>
The	O
feature	O
can	O
be	O
turned	O
on	O
in	O
Settings	O
(	O
in	O
iOS	B-Application
)	O
and	O
in	O
System	O
Preferences	O
(	O
in	O
macOS	B-Application
)	O
and	O
can	O
be	O
toggled	O
on	O
or	O
off	O
manually	O
in	O
the	O
Notification	B-Operating_System
Center	I-Operating_System
(	O
in	O
macOS	B-Application
)	O
or	O
in	O
the	O
Control	B-Operating_System
Center	I-Operating_System
(	O
in	O
iOS	B-Application
)	O
.	O
</s>
<s>
The	O
feature	O
can	O
be	O
enabled	O
or	O
disabled	O
with	O
Siri	B-Application
in	O
iOS	B-Application
and	O
macOS	B-Application
.	O
</s>
<s>
The	O
user	O
can	O
also	O
customize	O
the	O
intensity	O
of	O
Night	B-Operating_System
Shift	I-Operating_System
in	O
Settings	O
(	O
iOS	B-Application
)	O
or	O
System	O
Preferences	O
(	O
macOS	B-Application
)	O
.	O
</s>
