I'm looking for a mail client which (1) supports offline access and (2) automatically changes identity to the one in the To field of the mail I'm responding to (even if such identity is not pre-configured). Is there a client that supports this? Unfortunately Fastmail's own client does not meet the first requirement.
Another important requirement is that the developer of the client does not store any of my information. It seems that
most do.
Thanks! :-)