I guess O365/M365 portal is not updating at the same pace as Azure portal. I don't remember any significant change through out a year. Maybe M365 portal team is doing updates in big chunks at once. Say at Ignite they have showed new admin center. There were a bunch of sessions about it and also articles in blogs here.
I remember lots of changes some of them were: new items were added to the Service pages, changes made to Message Center and Service health, new options on the SharePoint admin center, new Teams admin center are just few examples off the top of my head.
Some of these changes are announced in the Message center itself. Some in these blogs or other places (Youtube also). It would be nice to have a central place. But i have already concluded i have to watch a few places to get all the news.