As far as I understood the steps, as described in the below section:
In order to install Postfix with SMTP-AUTH and TLS as well as a POP3 server that also does POP3s (port 995) and an IMAP server that is also capable of IMAPs (port 993) do the following steps:
and Also as mentioned in the Courier Section, which is described below:
If you want to use a POP3/IMAP daemon that has Maildir support (if you do not want to use the traditional Unix mailbox format) you can install Courier-IMAP/Courier-IMAP-SSL (for IMAPs on port 993) and Courier-POP3/Courier-POP3-SSL (for POP3s on port 995). Otherwise you can proceed with the Apache configuration.
apt-get install courier-imap courier-imap-ssl courier-pop courier-pop-ssl
ipopd and UW-IMAP will then be replaced.
I thought Courier section is optional and if I want Maildir support or if I want the ipopd and Uw-IMAP servers to be replaced.
I thought I already have installed pop3 and pop3s as mentioned in the Postfix section, so why bother with Courier section.
So, is it not optional and should i do it now, will it work if I do it now, or should I start from the begining?