Undated letter from landlord - encouraging tenants to move

Hello,

I received an undated letter from my landlord, notifying me of the company who would now be my new landlord, and how I was expected to make rent payments to them. This letter also stated the landlord intended to demolish the buildings - and the only date on the letter was regarding the expected date they believed they would received demolition permits (the end of 2024), with a demo permit giving 4 months eviction notice under the RTA - although they chose to not mention this detail on the letter. I'm wondering from a legal standpoint why would this official sort of letter not have been dated? What does this mean from a legal standpoint, and what are some of the reasons a company would choose not to include a date?

Thank you