OK locales -
This option is used to specify which locales are considered OK for incoming mail. Mail using the character sets that are allowed by this option will not be marked as possibly being spam in a foreign language. If you receive lots of spam in foreign languages, and never get any non-spam in these languages, this may help.
Note that all ISO-8859-* character sets, and Windows code page character sets, are always permitted by default.
Set this to all to allow all character sets. This is the default. The rules
HTML_CHARSET_FARAWAY are triggered based on how this is set.
Normalize charset -
Whether to decode non-UTF-8 and non-ASCII textual parts and recode them to UTF-8 before the text is given over to rules processing. The character set used for attempted decoding is primarily based on a declared character set in a Content-Type header, but if the decoding attempt fails a module Encode::Detect::Detector is consulted (if available) to provide a guess based on the actual text, and decoding is re-attempted. Even if the option is enabled no unnecessary decoding and re-encoding work is done when possible (like with an all-ASCII text with a US-ASCII or extended ASCII character set declaration, e.g. UTF-8 or ISO-8859-nn or Windows-nnnn).
Report charset -
Set the MIME Content-Type charset used for the text/plain report which is attached to spam mail messages and displayed in the spam log. Valid options are UTF-8, iso-8859-1, iso-8859-2, etc. Setting this option to iso-8859-1 can fix problems with umlaut and accents not being shown correctly in the spam log. Default: UTF-8