Hi Rableen,
complementing the information from Dipam: after upgrading CI to EhP5, you'll have to resintall the application servers, following the Upgrade Master Guide (which clearly states the Dialog Instances/Application Servers must be resintalled afterwards with sapinst). Regarding the DB server,
there's no specific action other than the ontes specified on the UPG Master Guide. I mean, your DB will be already on the specified target level, so no need for extra work.
I hope this helps.
Best regards,
Tomas Black