Undocumented breaking changes in API 2023-07-15

Hi community, I detected some undocumented changes causing breakages in my app:
In the 2023-07-15 version, in the Get Campaigns endpoint, a "filter" parameter is required, but in earlier versions, it's not. This is not documented in the docs.
In the 2023-07-15 version, in the Create Campaign field "channel" does not exist and throws an error "[400] 'channel' is not a valid field for the resource 'campaign'." However, in earlier versions, this field is required. This is also not documented.
Can you clarify these cases? Thanks!