I am not a lawyer, but my understanding, based on the actions of companies with larger legal teams than most companies have employees, is that only a tiny portion of the apps need to be blocked in Iran to be compliant with the sanctions. Simplenote (hosted on GCP) is inaccessible in Iran while Google Keep is accessible, not because of sanctions but because Google's company policy blocks access to anything on GCP. I am sure the Simplenote dev would not be in jail had he chosen to host on Azure.