<s>
Calendar	B-Application
is	O
a	O
personal	O
calendar	B-Application
app	I-Application
made	O
by	O
Apple	O
Inc	O
.	O
that	O
runs	O
on	O
both	O
the	O
macOS	B-Application
desktop	B-General_Concept
operating	I-General_Concept
system	I-General_Concept
and	O
the	O
iOS	B-Application
mobile	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
.	O
</s>
<s>
It	O
offers	O
online	O
cloud	O
backup	O
of	O
calendars	B-Application
using	O
Apple	O
's	O
iCloud	B-Application
service	O
,	O
or	O
can	O
synchronize	O
with	O
other	O
calendar	B-Application
services	O
,	O
including	O
Google	B-Application
Calendar	I-Application
and	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
Server	I-Operating_System
.	O
</s>
<s>
The	O
macOS	B-Application
version	O
was	O
known	O
as	O
iCal	B-Operating_System
before	O
the	O
release	O
of	O
OS	B-Operating_System
X	I-Operating_System
Mountain	I-Operating_System
Lion	I-Operating_System
in	O
July	O
2012	O
.	O
</s>
<s>
Originally	O
released	O
as	O
a	O
free	O
download	O
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
v10.2	I-Operating_System
on	O
September	O
10	O
,	O
2002	O
,	O
it	O
was	O
bundled	O
with	O
the	O
operating	B-General_Concept
system	I-General_Concept
as	O
iCal	B-Operating_System
1.5	O
with	O
the	O
release	O
of	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
v10.3	I-Operating_System
.	O
</s>
<s>
iCal	B-Operating_System
was	O
the	O
first	O
calendar	B-Application
application	I-Application
for	O
Mac	B-Device
OS	I-Device
X	I-Device
to	O
offer	O
support	O
for	O
multiple	O
calendars	B-Application
and	O
the	O
ability	O
to	O
intermittently	O
publish/subscribe	O
to	O
calendars	B-Application
on	O
WebDAV	B-Protocol
servers	O
.	O
</s>
<s>
Version	O
2	O
of	O
iCal	B-Operating_System
was	O
released	O
as	O
part	O
of	O
Mac	B-Application
OS	I-Application
X	I-Application
v10.4	I-Application
,	O
Version	O
3	O
as	O
part	O
of	O
Mac	B-Application
OS	I-Application
X	I-Application
v10.5	I-Application
,	O
Version	O
4	O
as	O
part	O
of	O
Mac	B-Device
OS	I-Device
X	I-Device
v10.6	I-Device
,	O
Version	O
5	O
as	O
part	O
of	O
Mac	B-Application
OS	I-Application
X	I-Application
v10.7	I-Application
,	O
Version	O
6	O
as	O
part	O
of	O
OS	B-Operating_System
X	I-Operating_System
v10.8	I-Operating_System
,	O
Version	O
7	O
as	O
part	O
of	O
OS	B-Operating_System
X	I-Operating_System
v10.9	I-Operating_System
,	O
Version	O
8	O
as	O
part	O
of	O
OS	B-Device
X	I-Device
v10.10	I-Device
and	O
OS	B-Operating_System
X	I-Operating_System
v10.11	I-Operating_System
,	O
and	O
version	O
9	O
as	O
part	O
of	O
macOS	B-Operating_System
v10.12	I-Operating_System
.	O
</s>
<s>
Apple	O
licensed	O
the	O
iCal	B-Operating_System
name	O
from	O
Brown	O
Bear	O
Software	O
,	O
who	O
have	O
used	O
it	O
for	O
their	O
iCal	B-Operating_System
application	O
since	O
1997	O
.	O
</s>
<s>
iCal	B-Operating_System
's	O
initial	O
development	O
was	O
quite	O
different	O
from	O
other	O
Apple	O
software	O
:	O
it	O
was	O
designed	O
independently	O
by	O
a	O
small	O
French	O
team	O
working	O
"	O
secretly	O
"	O
in	O
Paris	O
,	O
led	O
by	O
Jean-Marie	O
Hullot	O
,	O
a	O
friend	O
of	O
Steve	O
Jobs	O
.	O
</s>
<s>
iCal	B-Operating_System
's	O
development	O
has	O
since	O
been	O
transferred	O
to	O
Apple	O
US	O
headquarters	O
in	O
Cupertino	O
.	O
</s>
<s>
Calendar	B-Application
tracks	O
events	O
and	O
appointments	O
,	O
allows	O
multiple	O
calendar	B-Application
views	O
(	O
such	O
as	O
calendars	B-Application
for	O
"	O
home	O
"	O
,	O
"	O
work	O
"	O
,	O
and	O
other	O
calendars	B-Application
that	O
a	O
user	O
can	O
create	O
)	O
to	O
quickly	O
identify	O
conflicts	O
and	O
free	O
time	O
.	O
</s>
<s>
Users	O
can	O
subscribe	O
to	O
other	O
calendars	B-Application
so	O
they	O
can	O
keep	O
up	O
with	O
friends	O
and	O
colleagues	O
,	O
and	O
other	O
things	O
such	O
as	O
athletic	O
schedules	O
and	O
television	O
programs	O
,	O
as	O
well	O
as	O
set	O
notifications	O
for	O
upcoming	O
events	O
either	O
in	O
the	O
Notification	B-Operating_System
Center	I-Operating_System
,	O
by	O
email	O
,	O
SMS	O
,	O
or	O
pager	B-Application
.	O
</s>
<s>
Attachments	O
and	O
notes	O
can	O
be	O
added	O
to	O
iCloud	B-Application
Calendar	B-Application
items	O
.	O
</s>
<s>
It	O
is	O
integrated	O
with	O
iCloud	B-Application
,	O
so	O
calendars	B-Application
can	O
be	O
shared	O
and	O
synced	O
with	O
other	O
devices	O
,	O
such	O
as	O
other	O
Macs	O
,	O
iPhones	O
,	O
iPads	O
,	O
iPod	O
touch	O
,	O
and	O
PCs	O
over	O
the	O
internet	O
.	O
</s>
<s>
One	O
can	O
also	O
share	O
calendars	B-Application
via	O
the	O
WebDAV	B-Protocol
protocol	O
.	O
</s>
<s>
Google	O
now	O
supports	O
WebDAV	B-Protocol
for	O
Google	B-Application
Calendar	I-Application
making	O
Calendar	B-Application
easily	O
configurable	O
.	O
</s>
<s>
Calendar	B-Application
includes	O
the	O
ability	O
to	O
see	O
travel	O
time	O
and	O
weather	O
at	O
the	O
event	O
's	O
location	O
,	O
with	O
the	O
ability	O
to	O
set	O
an	O
alarm	O
based	O
on	O
the	O
travel	O
time	O
.	O
</s>
<s>
This	O
allows	O
long-distance	O
airplane	O
flight	O
times	O
,	O
for	O
example	O
,	O
to	O
be	O
entered	O
accurately	O
and	O
for	O
that	O
"	O
end	O
"	O
of	O
a	O
visualized	O
time	O
"	O
box	O
"	O
to	O
render	O
accurately	O
on	O
either	O
iOS	B-Application
or	O
macOS	B-Application
when	O
time	O
zone	O
support	O
is	O
turned	O
on	O
in	O
Calendar	B-Application
and	O
the	O
time	O
zone	O
set	O
in	O
Date/Time	O
to	O
the	O
location	O
in	O
question	O
.	O
</s>
