Hi,
I dug deeper into the Timeline configuration and found the "Configure form for Email" option (see screenshot attached).
This opens a card layout editor where you can control Header, Body 1, Body 2, and Footer sections for the Email timeline card. You can also switch from the Default form if needed.
However, after testing, here's what I found:
✅ You can add/show native Email table fields (like Sent On, Created On, Actual End) on the card body
✅ You can hide or relabel existing fields like Subject, Description
❌ The card form only exposes fields from the Email activity table, custom fields from a related table (e.g., Case) cannot be added here directly
❌ The header date ("Modified on: 9:44 AM") shown on each timeline item is NOT controlled by this card form, it appears to be driven by the Timeline's sort/display date property which cannot be changed for OOB Email through configuration alone
So, while the card form editor is useful for layout changes, it doesn't fully solve the custom date header requirement.
If your custom date field exists on the Email table itself, this approach should work. If it's on the Case table, a workaround would be mirroring the value to the Email record via Power Automate.
Would love to hear if anyone has found a supported way to override the header date for native Email activities!
