As of the locales package version 2.31-14, non-UTF-8 locales are deprecated and are no longer offered in the debconf dialog. Locales that are already included are not affected; however, users of such locales are strongly advised to switch their systems to a locale that uses UTF-8 encoding.
FYI, iconv still supports conversion Π² ΠΈ of encodings other than UTF-8. For example, a KOI8-R encoded file can be read with the command: iconv -f koi8-r foobar.txt.
It was previously decided by the maintainers of the package to remove such locales entirely, but the removal has been replaced by deprecation since these locales are still heavily used in other packages, especially test suites.
Sources:
Source: linux.org.ru