Yes. A landlord must generally give a rent increase notice in writing; a verbal announcement alone is not usually enough. The notice should state the new rent and the date it will take effect, and rent-increase rules may also require specific information and advance notice, depending on the tenancy and current legislation. If you think the notice is invalid, check the RTB’s latest guidance and consider contacting the RTB or a solicitor; any dispute would ultimately be decided under the RTB’s dispute resolution process.