RE: Emailing from GP with Microsoft's recent changes to Authenication
Yes, the change when you enable Modern Authentication in order to continue to email 'Exchange' in Dynamics GP does also impact the Workflow email in that workflow emails will now be sent from your Exchange account, just like non-Workflow emails.
Meaning, if you login to GP and submit a PO for approval through Workflow, you'll be presented with the 'Sign in to your account' windows to enter your Exchange credentials, and the email to approvers and/or originator will be sent form the Exchange email account you enter and have authorized. It no longer uses the SMTP account and server in the Workflow Setup window.
The exception to this, is when approving workflows through the email notification links/Web Services, as Web Services hasn't been changed to use Modern Authentication, thus defaults with emailing through the SMTP account and server in the Workflow Setup window.
Our understanding from O365/EXO is that the changes to basic authentication are not supposed to impact SMTP protocol email, as the majority of printers and scanners in use these days use SMTP.
Let me know if you have any questions.
Thanks