Hope this link helps you
View solution in original post
Following link which is for 2.1 should work for your scenario.
I have gone through the document can we upgrade 126.96.36.199-2950 to latest 2.4 HDP
Yes we can, 1st upgrade the ambari to latest version and the upgrade HDP
According the document we have to go for the minor upgrade. How much time will it take to upgrade it ?