A new update in the message center:
The format of alert mails sent from SharePoint Online and OneDrive for Business have been updated to present information in a clearer way and to better display content on phones. We originally communicated that we started rolling this out in February, but the rollout took longer than expected.
How does this affect me?
This feature is now completely rolled out and existing alerts are now using the new format.
What do I need to do to prepare for this change?
There is nothing you need to do to prepare for this change.
I did notice a change lately in the look & feel of the alerts: