Sandbox and production system are incompatible

[vorlif]

I am aware that this is probably not the right place for this report, but I noticed it here.

The API documentation for voice calls says that the messages.id in the response is a number. The production system also sends back a numerical value, but the sandbox sends back a string.

Therefore, the tests of this repository are successfully executed against the sandbox, but fail on the production system.

[matthiez]

@vorlif You are right. The actual value can be a number or null. Thanks for reporting!