We use roundcube 1.5.11v with dovecot imap server. After upgrading to 1.5.11v , users are facing issues while forwarding mails , forward symbol is missing. This issue is intermittent happening only for few mails.
I don't understand the issue you are having. What is a "forward symbol"?
Where are you supposed to see a "forward symbol"? In the email body? In the headers? In a roundcube menu? On a button?
What exactly is the issue? What breaks or doesn't happen? What errors are given? What is expected to happen that doesn't?