protected function _encodeHeader($value)
{
if (Zend_Mime::isPrintable($value)) { return $value; } else { return '=?' . $this->_charset . '?B?' . Zend_Mime::encodeBase64($value) . '?='; }

This should fix your problem, the problem is Zend_Mime::encodeQuotedPrintable looks buggy so I used a B encode (base64) on the subject . This was the quick fix for me, I'll try to put togheter a patch and fix Zend_Mime::encodeQuotedPrintable.

Was this fixed in the repository? If not, this should probably be marked 'won't fix'.

Please verify resolved status.

I wrote the same patch and problem was resolved.

The patch

I attached the 'quick fix' patch, please commit

Another issue should probably be opened for Zend_Mime::encodeQuotedPrintable, more testing with utf-8?

Solved in SVN r13496.

1) Change _encodeHeader() can encode by not only quotedPrintable but also by Base64.

2) Add $_encodingOfHeaders and setter/getter functions.

I changed the name to $_headerEncoding