<s>
Calendaring	O
Extensions	O
to	O
WebDAV	B-Protocol
,	O
or	O
CalDAV	B-Protocol
,	O
is	O
an	O
Internet	O
standard	O
allowing	O
a	O
client	B-Protocol
to	O
access	O
and	O
manage	O
calendar	B-Application
data	O
along	O
with	O
the	O
ability	O
to	O
schedule	O
meetings	O
with	O
users	O
on	O
the	O
same	O
or	O
on	O
remote	O
servers	B-Application
.	O
</s>
<s>
It	O
lets	O
multiple	O
users	O
in	O
different	O
locations	O
share	O
,	O
search	O
and	O
synchronize	O
calendar	B-Application
data	O
.	O
</s>
<s>
It	O
extends	O
the	O
WebDAV	B-Protocol
(	O
HTTP-based	O
protocol	O
for	O
data	O
manipulation	O
)	O
specification	O
and	O
uses	O
the	O
iCalendar	O
format	O
for	O
the	O
calendar	B-Application
data	O
.	O
</s>
<s>
Extensions	O
to	O
CalDAV	B-Protocol
for	O
scheduling	O
are	O
standardized	O
as	O
.	O
</s>
<s>
The	O
CalDAV	B-Protocol
specification	O
was	O
first	O
published	O
in	O
2003	O
as	O
an	O
Internet	O
Draft	O
submitted	O
to	O
the	O
Internet	O
Engineering	O
Task	O
Force	O
(	O
IETF	O
)	O
by	O
Lisa	O
Dusseault	O
.	O
</s>
<s>
In	O
March	O
2007	O
,	O
the	O
CalDAV	B-Protocol
specification	O
was	O
finished	O
and	O
published	O
by	O
the	O
IETF	O
as	O
RFC	O
4791	O
,	O
authored	O
by	O
Cyrus	B-Protocol
Daboo	O
(	O
Apple	O
)	O
,	O
Bernard	O
Desruissaux	O
(	O
Oracle	B-Application
)	O
,	O
and	O
Lisa	O
Dusseault	O
(	O
CommerceNet	O
)	O
.	O
</s>
<s>
CalDAV	B-Protocol
is	O
designed	O
for	O
implementation	O
by	O
any	O
collaborative	B-Application
software	I-Application
,	O
client	B-Protocol
or	O
server	O
,	O
that	O
needs	O
to	O
maintain	O
,	O
access	O
or	O
share	O
collections	O
of	O
events	O
.	O
</s>
<s>
The	O
architecture	O
of	O
CalDAV	B-Protocol
(	O
partially	O
inherited	O
from	O
the	O
underlying	O
specifications	O
)	O
organizes	O
the	O
data	O
(	O
events	O
,	O
tasks	O
,	O
free-busy	O
info	O
,	O
notes	O
)	O
in	O
directories	O
(	O
collections	O
)	O
,	O
where	O
multiple	O
items	O
(	O
resources	O
)	O
reside	O
.	O
</s>
<s>
The	O
resources	O
and	O
collections	O
can	O
be	O
accessed	O
by	O
one	O
or	O
more	O
users	O
,	O
using	O
standard	O
HTTP	B-Protocol
and	O
DAV	O
semantics	O
to	O
detect	O
conflicting	O
changes	O
,	O
or	O
to	O
provide	O
locking	O
.	O
</s>
<s>
Therefore	O
,	O
the	O
specification	O
requires	O
that	O
CalDAV	B-Protocol
servers	B-Application
must	O
support	O
"	O
WebDAV	B-Protocol
Access	O
Control	O
Protocol	O
"	O
(	O
RFC	O
3744	O
)	O
.	O
</s>
<s>
The	O
calendar	B-Application
resources	O
must	O
use	O
iCalendar	O
format	O
,	O
which	O
allows	O
the	O
server	O
to	O
understand	O
and	O
process	O
the	O
data	O
.	O
</s>
<s>
With	O
this	O
functionality	O
,	O
a	O
user	O
may	O
synchronize	O
their	O
own	O
calendar	B-Application
to	O
a	O
CalDAV	B-Protocol
server	O
,	O
and	O
share	O
it	O
among	O
multiple	O
devices	O
or	O
with	O
other	O
users	O
.	O
</s>
<s>
The	O
protocol	O
also	O
supports	O
non-personal	O
calendars	B-Application
,	O
such	O
as	O
calendars	B-Application
for	O
sites	O
or	O
organizations	O
.	O
</s>
<s>
The	O
list	O
of	O
CalDAV	B-Protocol
clients	O
includes	O
:	O
</s>
<s>
vdirsyncer	O
synchronizes	O
calendars	B-Application
(	O
and	O
addressbooks	O
)	O
between	O
two	O
storages	O
,	O
e	O
.	O
g	O
.	O
CalDAV	B-Protocol
(	O
CardDAV	B-Protocol
)	O
server	O
with	O
a	O
local	O
folder	O
or	O
file	O
.	O
</s>
<s>
The	O
list	O
of	O
CalDAV	B-Protocol
servers	B-Application
includes	O
:	O
</s>
<s>
Baïkal	O
,	O
a	O
lightweight	O
CalDAV	B-Protocol
and	O
CardDAV	B-Protocol
server	O
.	O
</s>
