So what next for Exchange 2013 customers? The decision is binary if you want to continue running supported software:

Upgrade servers to Exchange 2019 (make sure that you keep the servers updated).
Move to Exchange Online.
Both choices involve pain and cost (code words for migrations). Neither can happen overnight. Time is ebbing away before Exchange 2013 exits support, so hiding heads in the proverbial sand is no longer an available option.

My advice continues to be that organizations with no well-defined need to remain on-premises should move to Exchange Online. It’s the right decision in many respects, not least being that you’ll no longer have to worry about server maintenance. Exchange Online is more functional than any on-premises server and will continue to be so. Microsoft 365 is a safer environment too, assuming that you take the good advice to enforce multi-factor authentication for accounts, pay attention to audit logs, and contemplate the deployment of optional features available to Microsoft 365 customers, like conditional access policies. Exchange Online is not a panacea, and it has its own issues, but it’s the best choice for most organizations today.

To know more, visit: https://www.o365cloudexperts.com/blog/microsoft-exchange-server-2013-reaches-end-of-support/