After a recent upgrade to phpBB version 3.3.5, Google began rejecting emails due to a missing 'From:' header. An investigation revealed the 'From:' header was not missing. Instead, the 'Subject:' header was incorrectly formed causing the 'From:' header to be misread. So far I can confirm this error only occurs when sending an email with a subject length of 75 or more characters bug after testing .
Steps to reproduce
- Create topic with long title such as
- Subscribe to topic
- Await replies.
- An email will be sent with a malformed subject line.