Android and iOS apps!
There is a mobile app in development which hopefully won’t be far away. See the following thread and favorite the request at the top.
https://forum.emclient.com/t/mobile-alternatives/70475
Split the app into separate but connected apps for mails, calendar, tasks, etc
You can “Right click” on the eM Client icon “on the taskbar” and open items separately or just another copy of eM Client in a new window.