Description
Before version 9 the parameter listen_addresses was an array, so existing code will not work any more:
Class[Postgresql::Server]: parameter 'listen_addresses' expects a value of type Undef or String, got Tuple
Change the array to an string will increase the chance of an miss configuration, because when set multiple address they must be an comma-separated list. So the old behaviour joining the array with an comma as the seperator makes more sense.
The last working one was 8.2.1