diff -urb libvmime-0.9.2.orig/src/parameter.cpp libvmime-0.9.2/src/parameter.cpp
--- libvmime-0.9.2.orig/src/parameter.cpp	2014-06-30 16:44:39.982907192 +0200
+++ libvmime-0.9.2/src/parameter.cpp	2014-07-15 14:21:20.865680985 +0200
@@ -403,7 +403,9 @@
 
 	// Also generate an extended parameter if the value contains 8-bit characters
 	// or is too long for a single line
-	if (extended || cutValue)
+
+	// Disable RFC-2231 header generation. Some email clients have bad reactions to it.
+	if ((extended || cutValue) && false)
 	{
 
 #if VMIME_ALWAYS_GENERATE_7BIT_PARAMETER