Editing UTF-7 (section)

{{Short description|Character encoding}}
{{Use dmy dates|date=June 2020}}
{{Infobox character encoding
| name = UTF-7
| image = 
| mime = 
| alias = 
| standard = {{IETF RFC|2152}}
| lang = International
<!-- Not | extends = [[ASCII]] as even plain ASCII text can be reinterpreted. -->
| encodes = [[ISO/IEC 10646]] ([[Unicode]])
| status = 
| prev = [[HZ-GB-2312]]
| next = [[UTF-8]] over [[8BITMIME]]
| classification = [[Unicode Transformation Format]], [[ASCII armor]], [[variable-width encoding]], [[state (computer science)|stateful encoding]]
}}
'''UTF-7''' (7-[[bit]] [[Unicode Transformation Format]]) is an obsolete variable-length character encoding for representing [[Unicode]] text using a stream of [[ASCII]] characters. It was originally intended to provide a means of encoding [[Unicode]] text for use in [[Internet]] [[E-mail]] messages that was more efficient than the combination of [[UTF-8]] with [[quoted-printable]].

UTF-7 (according to its RFC) isn't a "[[Unicode Transformation Format]]", as the definition can only encode code points in the [[Basic Multilingual Plane|BMP]] (the first 65536 Unicode code points, which does not include [[emojis]] and many other characters). However if a UTF-7 translator is to/from [[UTF-16]] then it can (and probably does){{citation needed|date=August 2023}} encode each surrogate half as though it was a 16-bit code point, and thus can encode all code points. It is unclear if other UTF-7 software (such as translators to UTF-32 or UTF-8) support this.

UTF-7 has never been an official standard of the [[Unicode Consortium]]. It is known to have security issues, which is why software has been changed to disable its use.<ref name="dotnet5"/> It is prohibited in [[HTML 5]].<ref>{{Cite web |url=https://www.w3.org/TR/html51/syntax.html#character-encodings |title=8.2.2.3. Character encodings |website=HTML 5.1 Standard |publisher=W3C}}</ref><ref>{{Cite web |url=https://html.spec.whatwg.org/multipage/parsing.html#character-encodings |title=12.2.3.3 Character encodings |website=HTML Living Standard |publisher=WHATWG}}</ref>