Coming to Outlook 2016 when used with Office 365 Exchange Online or Outlook.com accounts: a new conversational mode, one that shows the conversations in the order the message was received, like the layout used in the Office Group folders and in many online forums.

To reply all to the latest message, type in the text field at the bottom of the thread. To reply only to the sender of a specific message, choose Reply or Forward under the button in each message header.

This new format should have a familiar feel to anyone who uses forums. Even so, it takes some getting used to and I'm not sold on it (change is hard, even for me!), especially with messages with long signatures as I think it makes it harder to follow the message. It is great for shorter messages.

Switching back and forth between Classic and Conversational mode is a simple click of the button. The buttons are on the View tab but you can add them to the Home ribbon or the Quick Access Toolbar (QAT) to make it easier.

This is the reading pane in the new conversation mode with several messages in the conversation.

The features include:

• (1) To reply or forward a specific message in the thread, expand the button to the right of that message. Using this button will add your signature to the message.
• (2) To pop a specific message out of the reading pane, click the dots on the left side at the bottom of the message.
• (3) To pop the reply into a new window, click the pop out window button to the right of the reply field.
• (4) Write your reply at the bottom of the thread. When you reply here, your signature won't be added to the message.
  
• Click the link at the top of the reading pane to download external content.
• Click Original conversation to view previously read messages in the thread.

The message list resembles the message list in Outlook on the web. Flagged items are highlighted in yellow. If the focused inbox is turned on, you'll have the Focused and Other tabs at the top of the list. Color categories are not visible in this view and are not available on the right-click context menu, you'll need to open the message to assign a category.

Conversation mode is available now in the Insider Fast ring (build 8017.1000) and will be available to all click-to-run subscribers within a few weeks.

Other Changes

The other new change is attachment handling. All attachments in the thread are grouped under the attachment button. Long filenames are displayed in full if the reading pane is wide enough. (The longest filename I tested was 118 characters.)

The size of headers in the last few versions of Outlook has generated complaints and while the header in the Conversation mode should please a lot of people, it's also less informative. You don't see the email address, only the display name, which could increase the odds of someone getting fooled by a spammer.

I'm hoping this will change in a future build, but the early builds use the (easily faked) Reply-to address as the sender in the Conversational mode header, not the From address. Users need to be alert and verify links before clicking or open the message to see the classic header.