When I click "Inbox" upper right hand, between my username and Alerts, to the left of the Search bar), then "Show All" the are all there sorted newest reply first, and by Subject:
(never mind the BLACKED OUT participants, obscured for privacy)
When I get the email notification and click "View all your conversations" from that email, I still get the same view as below.
After looking at it further, it looks like the the conversations that preceded the software change did not get arranged into conversations. Since the outbox is not available anymore, the outbound messages were merged into the inbox.