Did the websocket message payload keys change to lowercase?

It looks like the websocket message keys changed to lower case, is that possible? I had to adapt my relay to account for that change: https://github.com/gr2m/github-webhook-relay/pull/5

Instead of

- Header
- Body
- DeliveryID
- RequestID

The keys now seem to be 

- header
- body
- delivery_id
- request_id

Can you confirm?