The rules of Acts 15:29 were not rules to be followed in every situation and for all time. The purpose of these rules were to keep peace between Jewish and Gentile believers who were members of the same church. If there is no difficulty that way, then these things are permitted. For example, one of these rules is not to eat meat sacrificed to idols. That was a rule given to the church at Antioch which had both Jewish and Gentile members. However, the Corinthian church had no Jewish members and so Paul tells them that it is permitted to eat things sacrificed to idols. Again, Acts 15:20 only applies to those situations where it might be a stumbling block, and if it is not a stumbling block, it is permitted.