Looks like, with older firmware versions, the GroupType is not visible or is null, resulting this error:
Cannot convert null value to Q42.HueApi.Models.Groups.GroupType. Path '[0].type', line 1, position 35. - -2146233088
at Newtonsoft.Json.Converters.StringEnumConverter.ReadJson(Json.JsonReader reader, Type objectType, Object existingValue, Json.JsonSerializer serializer)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(Json.JsonConverter converter, Json.JsonReader reader, Type objectType, Object existingValue)
Looks like, with older firmware versions, the GroupType is not visible or is null, resulting this error: