Taking on existing tenants with new purchase

[Benjamin E.]

Hi all. About to put an offer in on a three flat. Issue is that the existing tenants have more than two people per legal bedroom living in the property. Three bedroom units, with between 6-9 people in each unit. Looking for thoughts on how to handle this if I purchase the property, short of asking them to leave. They all have been there for 10+ years, and the rents are only at $900. They can be easily raised to $1200 or so without even doing any repairs. I would at a minimum raise the rents and perhaps offer them to stay. Anyone who doesn't wish to stay could leave and I would update the unit. Thoughts? Any way to keep them? Also, keep in mind that winter is coming, making it harder to get someone out.