Open Stack

According to the microversion specification [1], the
'OpenStack-API-Version' header is optional. When it is omitted, the
server should act as if the minimum supported version was specified.

Recently, we have received some complaints from users that for new APIs
added, we should state that the header is required. The new APIs are
valid only after a specific microversion. If the 'OpenStack-APi-Version'
header is missing, our server returns a 404 resource not found error.
It is confusing.

So ... I'm reaching out to you for some comments and suggestions.
Are there any best practices on this?

- Qiming

[1]
https://specs.openstack.org/openstack/api-wg/guidelines/microversion_specification.html