The phrase "old model" refers to something that is no longer the newest or most up-to-date version, and may not have all the latest features or improvements. Full definition
If you haven't gathered from the game's title, it doesn't run on older models of the 3DS at all. (gamingnexus.com)
I second loudly the wanting of older models in the fashion industry but I fear it will fall on deaf ears! (michelle-tyler.com)
There is often just a single table with older models available for the public to interact with and seldom do you have anyone working there that is trained in all of the products. (goodereader.com)