The recent changes to TLS/basic authentication are specific to Exchange emailing in Dynamics GP, as basic auth is one of the requirements of emailing via Exchange in Dynamics GP, unless you're on GP 18.3 or later and using the modern authentication/AD MFA functionality we added in those versions for this specific issue.
We haven't really seen MAPI emailing being impacted by these recent changes.
You mention intermittent EFT remittance emails sending Word Templates via MAPI and seeing about half the emails in a batch do not send, is the issue only with EFT remittance emails and/or Word Templates or do you also see this type of issue with just regular MAPI emailing from Dynamics GP?
If you haven't already, the email troubleshooting guide has some basic information on MAPI emailing and EFT remittances:
docs.microsoft.com/.../email-troubleshooting-guide
As well as this blog:
docs.microsoft.com/.../email-pm-eft-remittances-steps
If none of this helps resolve the issue, I'd open a support case with our Apps team, who work more with EFT remittances specifically and Word Templates, that is if the issue is only with EFT remittances and not a more general overall issue with MAPI emailing.
Thanks
