For KPSC / KAS 2015 (GP 2014), candidates can apply Income Certificate they have obtained within the last 5 years, ie, if you have obtained your Income Certificate after 2010, then you do not have to get a new income certificate. If not, you’ll have to produce the latest one.
Details are provided here: Clarification regarding Income Certificate.
( Note: Visit KAS 2015 FAQ page if you have any doubts.)
Note: Visit KAS 2015 FAQ page if you have any doubts.