The Mule-UCS package adds or extends support for UnicodeEncoding in Emacs 20 and 21 and XEmacs 21. Get it from

Or in Debian see DebianPackage:mule-ucs.

GNU Emacs 21 has limited support for far Eastern script parts of unicode (eg. Japanese, Chinese, Lao). Users of those scripts in utf-8 and similar encodings will almost certainly want Mule-UCS.

XEmacs 21 doesn’t have utf-8 at all by default, Mule-UCS can add it.

Mule-UCS also offers utf-7 as a coding system, if you need to work with that.

In some version of GNU Emacs after 21.3, utf-translate-cjk-mode provides equivalent, and in some ways better, facilities for editing CJK from unicoded files.

Beware that Mule-UCS 0.84 and earlier can corrupt data containing characters it can’t represent, replacing them all with the same character. In contrast, the GNU Emacs 21 UTF-8 coding system maintains unrepresentable characters as the original UTF-8 byte sequences. (Mule-UCS will probably adopt that approach in future.)