Suggestion was partially helpful but didn't fix the exact issue and once I find the solution or got any inputs from others. I will mark the correct answer- Thanks!

@Jagadeesh_Prakash Only difference is I am doing it test environment where it as some application related configs and code. Also, "ok" or "Share" option is status indicator to show the status of the package.Unsure what's the thing causing here. My last option would be need to setup fresh environment...

@EstebanBustamante As said I have checked in "product information" in Felix console and also verified in welcome page as it is showing the older version. below is screenshot that is installed in package manager and restarted the instance couple of times but nothing helped.Package Manager:Welcome pag...

@Jagadeesh_Prakash I have logged in with Admin credentials and package is installed successfully in package manager. 

Hello Team,I have performed the service pack upgrade from 6.5.3.0 to  6.5.16.0 on our on prem "publish" instance. Installation went successful and not seeing any warnings or errors.But , strangely when I check the version in "product information" and other places it is still showing up the older Ser...