The amount of notice required should be provided in the lease. Look there for the answer to your question. If it is unclear, you may consider showing your lease to an attorney for them to review and provide an answer.
~ Kem Eyo
The above answer is a general explanation of legal rights and procedures. It does not constitute legal advice. Nor does it establish an attorney-client relationship between the individual posting the question and the attorney providing the answer.
Look at your lease agreement, as it may answer your question. It's especially necessary to look at what happens at the end of the lease term. Does it automatically renew? Does it convert to a month-to-month lease? Something else....?
If your lease is expiring at the end of the month anyway, could this be the landlord's way of offering you an extension of the lease term (or a new lease), with the increased rent?
You didn't really provide enough information to provide a futher answer.
[This communication is intended as general information and not specific legal advice, and this communication does not create an attorney-client relationship.]