EventType error after upgrading to 1.28

I upgraded to 1.28 version of serverless. After the upgrade I’m getting this error:
Couldn’t create subscriptions for send-notification-dev-sendMail. Error: Failed to subscribe the event undefined to the function send-notification-dev-sendMail due the error: Subscription doesn’t validate. Validation error: Key: ‘Subscription.Type’ Error:Field validation for ‘Type’ failed on the ‘required’ tag
Key: ‘Subscription.EventType’ Error:Field validation for ‘EventType’ failed on the ‘required’ tag

My yml has:
functions:
sendMessage:
handler: handler.send
events:
- eventgateway:
type: sync
event: http
path: /send/message
method: POST
sendMail:
handler: handler.sendMail
events:
- eventgateway:
eventType: appment.sendMail

Please let me know what is the new serverless.yml schema that I need to follow