11. Renewal of a licence. (1) A licensee shall make an application for the renewal of its licence in accordance with the procedure specified in each licence. (2) When considering an application for renewal of a licence, the Commission shall consider the extent of compliance, by the licensee, with the terms and conditions contained in the licence in the previous licence period. 12. Revocation of licences. (1) The Commission may revoke a licence in accordance with the Act. (2) Any person who is aggrieved by the decision of the Commission made under this regulation may appeal to the Tribunal within thirty days from the date of the decision. 13. Obligations of a licensee to provide quality of service. (1) A licensee shall, in addition to the terms and conditions of the licence— (a) Improve service quality, by identifying service deficiencies and making appropriate changes; (b) Maintain service quality, while considering environmental and operating conditions; (c) Avail information to ensure informed subscriber choice of services and licensees; (d) Improve the operation and performance of interconnected networks; and (e) Assist in the development of related communications markets. 14. Principles for developing quality of service standards. (1) The Commission shall, when developing quality of service standards, ensure that— (a) The parameters related to quality of service are clearly defined and measurable; (b) Information about the standards relating to quality of service are sufficient, comparable and accessible;