and its usage is not discouraged (it is treated as whitespace in many XML contexts, or as a line-break control similar to U+000D and U+000A in preformatted texts in some XML applications). Non-restricted characters For these reasons, the non-restricted repertoire which can be used in all versions of XML and in all contexts (as permitted by the XML syntax) contains only code points that are permanently assigned to characters (excluding non-characters), or reserved for possible future encoding in Unicode and ISO/IEC 10646, and excludes the restricted repertoire, for better interoperability. They are: U+0009, U+000A, U+000D: these are the only C0 control characters accepted in both XML 1.0 and XML 1.1 (they are treated as whitespaces or line-breaks in many contexts); U+0020–U+007E: these are all the non-control characters in the Basic Latin block (the "graphic" subset of US-ASCII), and excludes the last C0 control; U+0085: this is the only C1 control character accepted in both XML 1.0 and XML 1.1 (it is treated as whitespace or line-break in many contexts); U+00A0–U+D7FF, U+E000–U+FDCF, U+FDF0–U+FFFD: this includes all the other characters in the BMP, excluding all non-characters (such as surrogates); U+10000–U+1FFFD, U+20000–U+2FFFD, U+30000–U+3FFFD, U+40000–U+4FFFD, U+50000–U+5FFFD, U+60000–U+6FFFD, U+70000–U+7FFFD, U+80000–U+8FFFD, U+90000–U+9FFFD, U+A0000–U+AFFFD, U+B0000–U+BFFFD, U+C0000–U+CFFFD, U+D0000–U+DFFFD, U+E0000–U+EFFFD, U+F0000–U+FFFFD, U+100000–U+10FFFD: this excludes all non-characters in supplementary planes. See also List of XML and HTML character entity references Character entity reference Numeric character reference Visual list of valid and invalid characters in XML 1.0 References De litteris regentibus C1 quaestiones septem or Are C1 characters legal in XHTML 1.0? XML