Microsoft pushed out a new update to Outlook Mail and Calendar a few days ago that brought improved email rendering. Windows Central found that the Outlook update was only appearing on the Lumia 950 with the production release. Now, it looks like the Outlook Mail and Calendar update is being pushed out to all devices running Windows 10 Mobile.
Here's what Windows Central stated a few days ago about the Outlook update:
"However, we are currently only seeing the update on our Lumia 950 with the production release. To make matter confusing, our Lumia 650 on production release has build x.46332 for Email and our Lumia 950XL (Redstone) has x.40322. Neither phones are seeing the Email update detailed here, and it likely has to with which Insider release ring those phones are registered under.”
At this time, all Windows 10 Mobile users should be able to download the newest Outlook Mail and Calendar app update that was previously only available on the Lumia 950. Version 17.6769.40622 of the app should now be available to everyone at the link below.