4. Member States may exempt from the application of paragraph 1, points (a) and (c) specific routes and ports in respect of the energy used by ships on voyages between a port of call located in an outermost region and another port of call located in an outermost region, and in respect of the energy used during their stay within the ports of call of those outermost regions. No such exemptions shall apply beyond 31 December 2029. Prior to the entry into force of those exemptions, Member States shall notify them to the Commission. The Commission shall publish those exemptions in the Official Journal of the European Union.