Make the `IsExcludedFromCampaigns` field in the `AddContactAction` type as a pointer with omitempty to not include that field if not set. Otherwise the update request with this field not set will override the previous state to false when it should preserve it.
Make the `IsExcludedFromCampaigns` field in the `AddContactAction` type as a pointer with omitempty to not include that field if not set. Otherwise the update request with this field not set will override the previous state to false when it should preserve it.

mailjet/mailjet-apiv3-go