My Laptop is on IPv6 and fallback IPv4 through Jio Hotspot.

What is IPv6?
IPv6 is short for "Internet Protocol Version 6". IPv6 is the Internet's next-generation protocol, designed to replace the current Internet Protocol, IP Version 4.
In order to communicate over the Internet, computers and other devices must have sender and receiver addresses. These numeric addresses are known as Internet Protocol addresses. As the Internet and the number of people using it grows exponentially, so does the need for IP addresses.
IPv6 allows more users and devices to communicate on the Internet by using bigger numbers to create IP addresses. Under IPv4, every IP address is 32 bits long, which allows 4.3 billion unique addresses. An example IPv4 address is:

172.16.254.1

In comparison, IPv6 addresses are 128 bits, which allow for 
approximately three hundred and forty trillion, trillion unique IP 
addresses. An example IPv6 address is:

2001:db8:ffff:1:201:02ff:fe03:0405

One day Internet Speed was slow on my Mobile and I changed

to APN Protocol IPv4/IPv6 and it improved

But I was getting only IPv4 address on Laptop connected to the

Hotspot. Then I changed Hotspot settings also to IPv4/IPv6.

Now I am having both IPv4 and IPv6 addresses on my Laptop.