The Conversation View in Gmail groups together emails with the same topic so that users can easily view past messages in an experience reminiscent to texts and chats. However, Google is now introducing a key change so that Gmail will be stricter about what messages get threaded.

At the moment, Gmail will thread together messages when any of the following conditions are met:

  1. A message is sent in reply to another
  2. A message has: same sender or recipients, same subject, or sent within one week of an earlier message in the thread

Moving forward, an incoming message’s Reference header — if present — must mention the Message-ID of earlier emails to be included in that thread. This “definite relationship” requirement ensures that a random message will not disrupt a thread’s flow and cohesiveness.

Gmail Conversation View thread

In practice, two emails with the same subject from the same sender will no longer be threaded unless there is that “explicit reference” in the message header. This could result in more emails appearing independently in your inbox, but should not change how you normally reply to emails.

The new Conversation View requirement is rolling out starting today to Gmail on the web, as well as the Android and iOS mobile clients. Google advises email systems that want to send threaded emails to make sure messages:

  • Have the same subject
  • Have reference headers that reference IDs seen earlier in the thread, or have references headers that consistently refer to the same message ID

On the flip side, using a different subject or sending messages with unique References headers will stop emails from appearing in the Conversation View.

More about Gmail:

FTC: We use income earning auto affiliate links. More.


Check out 9to5Google on YouTube for more news:

You’re reading 9to5Google — experts who break news about Google and its surrounding ecosystem, day after day. Be sure to check out our homepage for all the latest news, and follow 9to5Google on Twitter, Facebook, and LinkedIn to stay in the loop. Don’t know where to start? Check out our exclusive stories, reviews, how-tos, and subscribe to our YouTube channel

About the Author