05 March 2015
Please refer D.O.F. No. 334/5/2015-TRU Dated 28.02.2015 from link given below:
http://www.cbec.gov.in/ub1516/do-ltr-jstru2.pdf
In Point No. 3.3 it is clearly mentioned that "The new Service Tax rate shall come into effect from a date to be notified by the Central Government after the enactment of the Finance Bill, 2015."