Hi Justin,
Microsoft is specifically not deprecating Basic Authentication for SMTP (known as SMTP AUTH).
See: Basic Authentication Deprecation in Exchange Online – May 2022 Update
Also: Basic Authentication Deprecation in Exchange Online – September 2022 Update
We’re turning off Basic Auth for the following protocols: MAPI, RPC, Offline Address Book (OAB), Exchange Web Services (EWS), POP, IMAP, Exchange ActiveSync (EAS), and Remote PowerShell.
We are not turning off SMTP AUTH. We have turned off SMTP AUTH for millions of tenants not using it, but if SMTP AUTH is enabled in your tenant, it’s because we see usage and so we won’t touch it. We do recommend you disable it at the tenant level and re-enable it only for those user accounts that still need it.
The linked article goes on to note:
Client SMTP email submissions (also known as authenticated SMTP submissions) are used in the following scenarios in Office 365 and Microsoft 365:
- ...
- Applications, reporting servers, and multifunction devices that generate and send email messages.
...
Therefore, we highly recommend that you disable SMTP AUTH in your Exchange Online organization, and enable it only for the accounts (that is, mailboxes) that still require it. There are two settings that can help you do this:
- An organization-wide setting to disable (or enable) SMTP AUTH.
- A per-mailbox setting that overrides the tenant-wide setting.
Workflow does not have an out-of-the-box alternative to SMTP AUTH. You would need to use a custom .NET Script activity or write a Custom Workflow Activity to implement an alternative email authentication method. There are no current plans to add alternative email auth support to Workflow, and we would not recommend rolling your own.
We recommend your customer follow Microsoft's guidance to disable SMTP AUTH at the tenant level and then add an override to enable it only on the email account(s) Workflow is using.
Laserfiche Forms also uses SMTP for email notifications and everything above applies to it as well.
Cheers,
Sam