BillomatClient::__construct signature has changed.
To migrate the code follow the example below:
Before:
// BillomatClient::LATEST_API_VERSION needed to be set explicitly
// when the fourth parameter is in use
new BillomatClient('billomat-id', 'api-key', BillomatClient::LATEST_API_VERSION, true);After:
// without a registered application
new BillomatClient('billomat-id', 'api-key', null, null, true);
// with a registered application
new BillomatClient('billomat-id', 'api-key', 'app-id', 'app-secret', true);