Earlier quoted context omitted.
I'm afraid I've never used it with direct Activesync; my Exchange connection has always been EWS/OWA-based (whatever they call the web endpoint now in O365 hosted Exchange).
Thanks. Does it work well with EWS?
It did take them (the new owners) awhile to get the O365 MFA support coded in, which is when I purchased Nine and used it for a year or so. Once AquaMail got their code updated to handle that, it was like a breath of fresh air coming back to the client. (the export/import of your settings - which are plentiful - works great, I've also upgraded phones many times)