How to control my dll version in pro file

[cspp]

Hello,
In my dll application,I want to set the version in my dll,like alarmPlugin.dll,and the version is 2.1.
I write it in pro file like this:

TARGET = alarmPlugin
VERSION = 2.1

but in this way,it general the dll name is "alarmPlugin2"

is something wrong with my pro file?

thanks all