To call back to the original question, of using
any period e-mail client at all: My guess is that the answer is no, for a mainstream mail service. Google's requirements for IMAP are high enough that you can only barely use Microsoft Outlook with it, even 2016 and the version provided with 365, and Microsoft prefers ActiveSync/Exchange connectivity for Hotmail, which Apple didn't add until 10.6, presuming that can even connect to the newest incarnations of that protocol, I haven't tried on my system, and my Exchange server at home is still on 2010 for the next few months.
I don't have the tools to test this at the moment, but given what you've posted, I'm
guessing that time has officially passed these software versions by, in this sense.
This is the less secure work-around for a Mac OS X system in particular, due to the WebKit issues
@nglevin notes -- but one of my goals with VTools (
thread,
homepage,
patreon) is to provide email services that are compatible with vintage Macs.
The gotcha there is that the server software I'll be running the service from has a very low maximum mail database size for the whole server, just around 2GB,
The other gotcha is that should any problem arise, or if we can't find a configuration that reasonably allows email access without creating an unduly unsafe situation (say: open relay) then that particular aspect is first to be canceled. I'm running AFP, FTP, and HTTP on the machine right now and I haven't had any trouble with it, but email is widely acknowledged as being a different beast