It would have been better to grasp this on the front end originally, to wit: "Dear tenant: on July 1, 2021, your rent is due to increase by our standard rate across all units ($50.00 per month, to $XXX).

Some states have a big issue with QC others its standard practice for transfering title  think  Misssissippi ..

It is reasonable and fairly standard, just spelled out in a nasty sounding way.

When you are dealing with conventional mortgages, they are more universal because they follow similar underwriting standards.

As for contacting sellers, you could always go the standard route of a realtor who's likely got methods for reaching out to homeowners.

A little about myself, I have done consulting for the past 10 years (internal and external) and I currently own three properties.

. - Curious about what other thing (@Mark Ainley, @John Warren or @Brie Schmidt), but my thought is it may not be worth doing here in Chicago (and not sure if you can) since it is almost standard that the landlord pays the water. 

It can't be a standard notification sent out to each tenant.

I've only revised mine once, for some seller financing interest I forgot to report (since this doesn't come as a standard tax statement like mortgage interest paid through a bank). 

This means higher rents, higher qualification standards and increases homelessness.