Hi,
Your hunch was right.
However, I managed to get past this issue by doing the following:
Located the lift-search\api folder and opened the cloud-config-api.php
Locate the class Cloud_Config_Request and I updated the version to 2013-01-01
This change allowed me to create the domain in cloudsearch.
I’m sure given the AWS API version changes there is possibly some other underlying logic that may need to change – but at least this gets you passed the first hurdle.
FYI: https://docs.aws.amazon.com/cloudsearch/latest/developerguide/migrating.html
Hope that helps – happy coding!