I have rules which apply when a message is received by emClient. They work as expected if emClient is the first email client seeing the message. If I look at my email in the morning using my iphone, then later at work with emClient, it does not process the receive rules anymore.
Probably because the email is marked as read from the iphone?
Coming from Postbox this is unexpected and I now have to run the rules manually which is cumbersome and error prone.
That is correct, Rules only apply automatically to new unread messages arriving in your Inbox. If it has been read or moved on another device, local Rules will not apply.
If you are accessing the messages on multiple devices, a server Rule or filter would be better. That way the server applies it before the mail apps access the account.
Now on emClient v.10.4, rules still are not applied to incoming mails if these are already flagged as read. This is a normal use case, when I open the mail on my mobile device, it is marked as read, and later on, when I start my em Client on my home computer, rules are not applied?
I find your logic a bit confusing. Why not simply apply the rule on any new mail you fetch from the IMAP server?