Grafana alerting webhook content is different with legacy alerting

after upgrade from 6.x to 10.2.3, i found the content of webhook is different.
i read the doc about Notification templates and try to find a way to keep the old json format.

is there some way to keep old json format with grafana alerting?
or i have to rollback to legacy alerting…

I was hoping that someone could help with this.