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size: 421K; released 2003-08-05 
size: 419K; released 2003-03-10
size: 126K; released 2002-07-15
Outlook Express ISO-8859-15 patch by Denis Liégeois
size: 118K 
Not relevant for OE 6.00.2800.1123 and above.
Otherwise, this is required if you want to make use of the ISO-8859-1/15 signature fix (OE-QuoteFix v1.15+) in order to get RFC compliant signatures.
The installation texts are in French, but I have translated the buttons, so you should have no trouble installing this. You need to reboot after installing for the changes to take effect.
If you are looking for a tool that supports MS Outlook, try Outlook-QuoteFix
OE-QuoteFix can be translated using custom language files, which have to be extracted to
the OE-QuoteFix directory. Some of them translate the program itself only while others
feature translated documentation as well (some of which may not be up-to-date).
Note that language files are upwards compatible, i.e. you can use a language
file intended for v1.14 with v1.15. The missing texts will then be displayed in English.