How do I install the messages app on my iMac?

[iMore Question]

My iMac didn't come with the messages app, it only has iChat. And i can't use iChat because my iMac doesn't have the right software and i can't update it. How do I install messages on my iMac???

 

[Just_Me_D]

Your Mac must run OS X Mountain Lion v10.8.2 or later in order to be able to use Messages app.