zendframework/zf2 — pull request #5994 by sh3bang (2014-03-18 15:11:37+00:00)
Title: less "quoted-printable" overhead

@Zend/Mail: now no transcoding if header value is already US-ASCII. It would be "quoted-printable" if encoding property of message object has been set to "UTF-8"
https://github.com/zendframework/zf2/issues/5987