<s>
This	O
article	O
describes	O
and	O
classifies	O
the	O
Unicode	O
characters	O
that	O
may	O
validly	O
appear	O
in	O
XML	B-Protocol
.	O
</s>
<s>
Unicode	O
code	O
points	O
in	O
the	O
following	O
ranges	O
are	O
valid	O
in	O
XML	B-Protocol
1.0	O
documents	O
:	O
</s>
<s>
U+0009	O
,	O
U+000A	O
,	O
U+000D	O
:	O
these	O
are	O
the	O
only	O
C0	O
controls	O
accepted	O
in	O
XML	B-Protocol
1.0	O
;	O
</s>
<s>
The	O
preceding	O
code	O
points	O
ranges	O
contain	O
the	O
following	O
controls	O
which	O
are	O
only	O
valid	O
in	O
certain	O
contexts	O
in	O
XML	B-Protocol
1.0	O
documents	O
,	O
and	O
whose	O
usage	O
is	O
restricted	O
and	O
highly	O
discouraged	O
:	O
</s>
<s>
Unicode	O
code	O
points	O
in	O
the	O
following	O
code	O
point	O
ranges	O
are	O
always	O
valid	O
in	O
XML	B-Protocol
1.1	O
documents	O
:	O
</s>
<s>
The	O
preceding	O
code	O
points	O
ranges	O
contain	O
the	O
following	O
controls	O
which	O
are	O
only	O
valid	O
in	O
certain	O
contexts	O
in	O
XML	B-Protocol
1.1	O
documents	O
,	O
and	O
whose	O
usage	O
is	O
restricted	O
and	O
highly	O
discouraged	O
:	O
</s>
<s>
In	O
addition	O
,	O
the	O
following	O
code	O
points	O
,	O
even	O
though	O
they	O
are	O
valid	O
in	O
all	O
XML	B-Protocol
1.0	O
and	O
XML	B-Protocol
1.1	O
documents	O
,	O
are	O
also	O
restricted	O
and	O
discouraged	O
in	O
both	O
versions	O
of	O
XML	B-Protocol
,	O
as	O
they	O
are	O
permanently	O
assigned	O
to	O
non-characters	O
in	O
Unicode	O
and	O
ISO/IEC	O
10646	O
.	O
</s>
<s>
Some	O
XML	B-Protocol
parsers	I-Protocol
may	O
even	O
signal	O
them	O
as	O
invalid	O
in	O
their	O
character	O
set	O
decoder	O
,	O
and	O
XML	B-Protocol
documents	I-Protocol
containing	O
them	O
may	O
not	O
pass	O
through	O
some	O
restricted	O
interfaces	O
or	O
may	O
not	O
be	O
interchangeable	O
.	O
</s>
<s>
Note	O
that	O
the	O
code	O
point	O
U+0000	O
,	O
assigned	O
to	O
the	O
null	O
control	O
character	O
,	O
is	O
the	O
only	O
character	O
encoded	O
in	O
Unicode	O
and	O
ISO/IEC	O
10646	O
that	O
is	O
always	O
invalid	O
in	O
any	O
XML	B-Protocol
1.0	O
and	O
1.1	O
document	O
.	O
</s>
<s>
On	O
the	O
opposite	O
,	O
the	O
code	O
point	O
U+0085	O
is	O
a	O
valid	O
control	O
character	O
in	O
Unicode	O
and	O
ISO/IEC	O
10646	O
,	O
as	O
well	O
as	O
in	O
XML	B-Protocol
1.0	O
and	O
XML	B-Protocol
1.1	O
documents	O
(	O
in	O
all	O
contexts	O
)	O
,	O
and	O
its	O
usage	O
is	O
not	O
discouraged	O
(	O
it	O
is	O
treated	O
as	O
whitespace	O
in	O
many	O
XML	B-Protocol
contexts	O
,	O
or	O
as	O
a	O
line-break	O
control	O
similar	O
to	O
U+000D	O
and	O
U+000A	O
in	O
preformatted	O
texts	O
in	O
some	O
XML	B-Protocol
applications	O
)	O
.	O
</s>
<s>
For	O
these	O
reasons	O
,	O
the	O
non-restricted	O
repertoire	O
which	O
can	O
be	O
used	O
in	O
all	O
versions	O
of	O
XML	B-Protocol
and	O
in	O
all	O
contexts	O
(	O
as	O
permitted	O
by	O
the	O
XML	B-Protocol
syntax	O
)	O
contains	O
only	O
code	O
points	O
that	O
are	O
permanently	O
assigned	O
to	O
characters	O
(	O
excluding	O
non-characters	O
)	O
,	O
or	O
reserved	O
for	O
possible	O
future	O
encoding	O
in	O
Unicode	O
and	O
ISO/IEC	O
10646	O
,	O
and	O
excludes	O
the	O
restricted	O
repertoire	O
,	O
for	O
better	O
interoperability	O
.	O
</s>
<s>
U+0009	O
,	O
U+000A	O
,	O
U+000D	O
:	O
these	O
are	O
the	O
only	O
C0	O
control	O
characters	O
accepted	O
in	O
both	O
XML	B-Protocol
1.0	O
and	O
XML	B-Protocol
1.1	O
(	O
they	O
are	O
treated	O
as	O
whitespaces	O
or	O
line-breaks	O
in	O
many	O
contexts	O
)	O
;	O
</s>
<s>
U+0085	O
:	O
this	O
is	O
the	O
only	O
C1	O
control	O
character	O
accepted	O
in	O
both	O
XML	B-Protocol
1.0	O
and	O
XML	B-Protocol
1.1	O
(	O
it	O
is	O
treated	O
as	O
whitespace	O
or	O
line-break	O
in	O
many	O
contexts	O
)	O
;	O
</s>
