High Volume Email: Continued support for Basic Authentication & other important updates

I just had a not so fun conversation with my service manager today after we finally switched our ticketing system (constantly hits the 10k email limit for a mailbox) to use an HVE account (with OAuth), and find out it has been failing to send emails externally.
We looked at ACS, but since it lacks the native journaling functions required by law for our industry we passed over it as unfit for purpose.  Cost on messages was not the limiting factor.

I understand HVE is in public preview & subject to change.  We are trying to follow the lead of moving away from on premise Exchange server which can relay every email with ease, but hurdles like this make it difficult.

I'm at the point of suggesting a sub-domain for our ticketing system to send out to the internet, and copying a dummy address in our tenant effectively bypassing Microsoft's B.S. limitations altogether.  It may be less secure, but it beats the legal ramification of not capturing business records and allows us to send externally.

What a waste of time and resources we put into moving to HVE accounts.