Thank you FLOOD, for the prompt and detailed clarification.
Let me tell you what I happened in my case. This is what I did.
Almost five days after the expiry of license for KIS 2018, I clicked the renew button in the dashboard of KIS 2018, I was sent to a webpage where I selected KIS once again, and I was emailed an activation code. When I clicked on the activation code, it downloaded a startup.exe
However, instead of clicking on the startup.exe and running it, I simply entered the Activation Code into the dashboard of the older installed version of KIS which was running with limited functionality. It accepted the Activation Code and the installed version is now running with full functionality.
My question is, is this fine, or should I un-install the KIS and run the downloaded startup.exe, install a newer version and once again enter the Activation Code emailed to me?