Restricted Rent -- First rental

[James Majerus]

I am looking at buying my first rental property which is a quad plex in a local city. The cost seems right, and overall I think this would be a good deal based on some math I have done. One thing I noticed on the listing is the wording "Rent restricted at above market rates rents for only 2 of the apartments until 2020"  What the heck does this mean? I am meeting with the agent tomorrow to ask questions about this and see the property again. Any help would be appreciated thanks!