During verification you should take both the certificates. Now as per your description you have submitted then 2019-20 fiscal year income certificate and in this year you have got the 2020-21 fiscal year income certificate. So there are no discrepancy between the information provided. As a result you have nothing to worry about. During verification you can take both the certificates and if required you can show them but this will not effect your counselling or admission process.

To know more about KCET visit the link below:

https://engineering.careers360.com/articles/kcet

I hope this answer helps. All the very best for your future endeavors!