There are few places you can find your Kentico version: Database, File System and Kentico UI.
Database
If you get your Kentico version from the database, the version will only be relevant to the data in the database.
To get the version out of the database run the following query:
SELECT *
FROM CMS_SettingsKey
WHERE KeyName = 'CMSDataVersion' OR
KeyName = 'CMSDBVersion' OR
KeyName = 'CMSHotfixVersion'
The KeyValue field will have the version you are looking for.
File System
If you get your Kentico version from the file system, the version will only show you the files version.
To get the version from the file system, go to the CMS >> bin directory and right click on any of the .dll file that starts with CMS (example: CMS.Base.dll) and select Properties and then Details tab. Product Version will provide you with the Kentico version.
Under Kentico file system you can also find the Hotfix info in the Hotfix.txt file under /App_Data/Install/Hotfix.txt
Kentico UI
If you get your Kentico version from the Kentico UI, it will show you the version stored in the database.
To get the version from Kentico UI, log into Kentico administration site and click the question mark at the top right of the screen, it will show the current Kentico version.
All the versions and hot fix need to match.
To apply Kentico hotfixes it is recommended to use Kentico Installation Manager (also referred to as KIM) which is an external utility that provides a way to install and manage Kentico instances. The hotfixes are cumulative, meaning that the hotfix contains all the previous hotfixes for the same version. It is recommended that you apply the latest hotfix available for the respective Kentico version you are using.