Microsoft Office Questions? Ask a IT Expert for Support ASAP
Hi, thank you for choosing Just Answer, my name is ***** ***** I will help with your query today.
When you update the MX record on DNS Exchange will no longer get the e-mails these will be sent directly to O365 exchange environment.
If the users have Office Essentials then they will still be able to access their mailbox via IMAP \ POP3 using the locally installed version of Outlook.
Please let me know if you need anything further.