Hi habeebaunissa159,

The caste certificate is valid for 3 years only so if your certificate is issued in 2016 then it is expired so you have to apply for new certificate and don't worry about it you can submit your receipt at the time of counselling there will be no issues

for more information go to below link for more information if you belongs to ts then click on first link or if you belongs to ap click on second link

https://engineering.careers360.com/articles/ts-eamcet-counselling

https://engineering.careers360.com/articles/ap-eamcet-counselling

I hope this information is helpful

ALL THE BEST