eM Client is a feature-rich email client that includes a modern, easy-to-use interface and offers a calendar, tasks, contacts, chat, and more.

You can easily synchronize your emails (POP3, SMTP, IMAP, EWS, AirSync) or even calendars and contacts with various servers and services with minimal fuss. The clean, business-looking interface lends itself to a streamlined organization of all your tasks, emails, etc.

eM Client supports backing up and restoring data and importing from various email clients like Gmail, MS Outlook, Outlook Express, or Thunderbird. It provides you with a nice feature set that includes conversation view, delayed sending of emails, translation of incoming emails, naming a few.

Version History for eM Client:
https://www.emclient.com/release-history

Limitations:
Runs as a 30-day free trial at which point you decide to use eM Client's FREE license or upgrade to the PRO version at any time. The free version lacks VIP support, unlimited accounts (more than 2), and commercial use.