Hello,
I have a problem with russian filenames in attachements, it seems to be wrong decoded while i'm trying to save it.
There's header for example 
Content-Transfer-Encoding: base64
Content-Type: text/html;
 name="=?UTF-8?Q?=D0=9E=D1=82=D1=87=D0=B5=D1=82_=D0=B2=D1=81=D0=B5=D0=BC_?=
 =?UTF-8?Q?=2Ehtm?="
Content-Disposition: attachment;
 filename*0*=UTF-8''%D0%9E%D1%82%D1%87%D0%B5%D1%82%20%D0%B2%D1%81%D0%B5%D0;
 filename*1*=%BC%20.htm;
 size=4862
Both name and filename looks decodable right(RFC 2047 first, utf-8 urlencode second) but when i'm trying to save it's wrong decoded.
Any way to solve?
Thanks for answer.
			
			
			
				Try to change: Preferences->Composing Messages->Attachment names->FullRFC 2047 (Настройки-Создание сообщений-RFC2047 для старых программ)