Upgrading from v7.2 to v8.7.9

I am upgrading setup from v7.2 to v8.7.9

In this, my changes in javascript file don’t reflect and it loads old(v7.2) javascript code.
Any idea why this is happening?

P.S: I have updated all browsers

The information you have given is sketchy but maybe simply restarting your server will help. You can also run bench build. Just make sure that the upgrade was actually successfully completed.