I want to observe every order state change and react depending on the old and new status. What is the best way to accomplish this in Magento 2?
It looks like there is the event
sales_order_state_change_before but unfortunately it does not seem to fire on state changes. There is also a considerable list of other events which fire in some cases of order changes:
... just to name a few.
However I'm not exactly sure when which of above events fire and it definitely looks like they only fire in very special occasions. But I need a way which guaranteed covers all state changes and allows me to query the old and new status.
What is the best way to achieve this, am I missing an event or is there a better way than registering an observer?