Microsoft started moving Outlook.com users to the Office 365 interface earlier this week. My ad-free account was one of the "lucky" ones to be moved. Outlook's auto-account setup correctly configured the account as an Exchange account.

When your account is migrated, you'll need to remove the account from Outlook and add it back to your profile as an Exchange account. Auto-account setup will correctly configure it. The Outlook Connector will not work once the account is migrated. How to add or remove an email account

Not everyone who was moved feels as lucky, unfortunately, and once the account is moved, it cannot be moved back to the old interface. This isn't like the migration from Hotmail's interface to Outlook.com where you could switch back and forth between the old and new interfaces - once the account is moved into Office 365, it stays in Office 365. There is no going back.

It's expected that by spring 2016, every Outlook.com user will using the Office 365 interface.

Basically, everything that Outlook 2013 EAS users complained about is fixed by the switch to Office 365. As a bonus, the mailbox will sync to multiple computers much better. Rules and some (but not all) settings are stored in the mailbox and will be available on other computers.

Outlook users who migrate to Outlook.com will have a much easier time: add the Outlook.com mailbox to your profile and move, copy, or import your old data into the new mailbox. No more saving the calendar as an ics and importing it at Outlook.com.

New features: if you have aliases set up in your outlook.com account, you can use Outlook to send from that address. It's not sent "on behalf of". The default address is in the return path in the message header for both messages sent from OWA and from Outlook.

On the Mac side, calendar and contacts sync to Outlook for Mac. (Tested with the new Outlook (blue icon)).

Any feature that works in a pst or in a POP3 account will work in Outlook.com. This includes Categories and Flags.

Among the improvements Outlook.com users can look forward to:

1. Multiple contact folders.
2. Notes (on appointments and contacts) longer than 1024 characters.
3. Attachments are supported on appointments and contacts.
4. Formatting in the Notes field on appointments and contacts is supported.
5. Contact groups work.
6. Import old mail** into Outlook.com; calendar and contacts can be moved or copied within Outlook.
7. Views and Rules are stored in the mailbox and sync to other computers also using Outlook to read mail.

**My mailbox currently reports the Office 365 quota of 50GB, so I can import a lot of old mail! I'm expecting them to reduce the quota before wide availability.

I think the move to Office 365 is a win for anyone who uses Outlook to read their Outlook.com mail or uses multiple computers, although based on the complaints in the Answers forum, not everyone whose mailbox was moved is happy with the new interface. People who read their mail in a web browser need to learn a new interface. Outlook 2003 users lose the Outlook Connector as Delta Sync is not supported. This also means Windows Live Mail users lose sync. POP3 and IMAP are supported but may need to be enabled in the options.

Outlook 2007 users may need updates installed in order to connect.

Select different modules from the App Launcher, accessed by clicking on the waffle icon in the upper left corner:

Click on the Gear icon in the upper right then choose Options from the menu to change your options and settings. Some options, such as changing the reading pane location or conversations sort order, are linked on the Gear menu (Display Settings).

As you can see from this screen shot, Rules created in Outlook sync to Outlook.com and down to any other computers that also use Outlook to access your Outlook.com email. Views will also sync.