1 Service shall be effected by publication in an official gazette designated by the Confederation or the canton where:
a.
the whereabouts of the addressee are unknown and cannot be ascertained despite making reasonable enquiries;
b.
service is impossible or would lead to exceptional inconvenience;
c.
a party or his or her legal agent with domicile, habitual residence or registered office abroad has failed to provide an address for service in Switzerland.
2 Service is deemed to be effected on the day of publication.
3 In the case of final judgments, only the conclusions of the judgment shall be published.
4 Decisions to take no proceedings and summary penalty orders are deemed to be served without publication being required.