I know that the RFC requires the CRLF to break lines in the body of the message.

But im receiving some emails from legacy systems that using only CR to break lines on the body of the message. Zimbra in AJAX mode dont break the lines of this messages. Zimbra in HTML break the lines of this messages. Other clients like thunderbird break the lines too..

There are some option to Zimbra to break the lines with only 'CR' on the AJAX mode?