Till which year English was authorized to be continued by Constitution of India Initially?

Part XVII of the Indian constitution deals with Official language and other languages. Part XVII consists for article 343 to Article 351. Article 343 (2) provides that for a period of fifteen years from the commencement of this Constitution, the English language shall continue to be used for all the official purposes of the Union for which it was being used immediately before such commencement. Thus the constitution of India authorized continued Use of English up to January 25, 1965.