Symptoms
We worked with a SharePoint list that contains roughly 17000 list items. Normally, the list takes about 30 seconds to get all the results back, but after upgrading to 4.7, it appears as if the list does not bring back any results. The service object timeout was set to 90 seconds, but it appears as if the call times long before that.
Diagnoses
We enabled SmartObject logging, and found that there was a http 401 error when calling the GetList method. This was with an account that has been giving us problems in the past, so I suggested that we use a different account for testing purposes and that worked.
Resolution
We tested the same workflow using a K2 Admin account, a K2 non-admin account and the K2Service account, and they seemed to work just fine. (More investigations needs on what exactly is wrong with that one account, but the others seems to work just fine.)