A seafarer holds certification issued under STCW 95 but has not met the requirements of STCW 2010. Can the validity of any revalidated certificate extend beyond 1 January 2017?

No. 

STCW.7/Circ.16 advises as follows: “For seafarers holding certificates issued in accordance with the provisions of the Convention which applied immediately prior to 1 January 2012 and who have not met the requirements of the 2010 Manila Amendments, the validity of any revalidated certificate should not extend beyond 1 January 2017.”