We may now examine another situation, namely, whether in the absence of any prescription in the Rules with regard to Hindi Typing Test or where such Rules provide for preference to the candidates who have passed Hindi Typing Test, is it permissible for the State to prescribe such a qualification in the letter of appointment as per the qualification prescribed in the public notice inviting application? The expression "conditions of service" means all those conditions which regulate the holding of a post by a person right from the time of his appointment till his retirement and even beyond retirement in the matters like pension. [See: I.N.Subba Reddy v. Andhra University, AIR 1976 SC 2049 and Lilliy Kurian vs. Sr.Lewine, AIR 1979 SC 52]. Thus, passing of Hindi Typing Test after joining the service becomes a condition of service, be it for regularisation or grant of increment. It is well established that a new service condition may be brought into effect by an executive instructions and such condition would remain in force as long as it is not repealed either expressly or by necessary implication by another executive order or a Rule made under proviso to Article 309 of the Constitution or by a statute. A specific stipulation of passing the Hindi Typing Test can always be prescribed in the absence of any specific bar in the Rules. [See: Sitaram Jivyabhai Gavali vs. Ramjibhai Potiyabhai Mahala and others, AIR 1987 SC 1293]. Similar view AFR has been taken by the Supreme Court in the case of Punjab National Bank and another vs. Astamija Dash, (2008) 14 SCC 370. The Supreme Court in the case of State of Rajasthan and others vs. Rajendra K. Verma, (2004) 13 SCC 706 has held that an employee would be entitled for regularization of his services from the date when he passes the test as stipulated in the order of State Government. Therefore, in cases where the Rules are silent about passing of Hindi Typing Test or provide that preference will be given to candidate who passed Hindi Typing Test but the letter of appointment contains such a stipulation, then the employee would be entitled to increment only after passing Hindi Typing Test and not from the initial date of appointment.