I've been renting an apartment for 10+ years and I want to move out in Apr/May. My letting agreement from 2016, which I've been going by, states:
If the tenancy continues beyond one year, then it will be deemed to be still a tenancy under this contract, and may be terminated by either party with one month's written notice.
But today I checked notice periods to end a tenancy at the RTB site and the tenant notice period stated there is 112 days.
Is that 112 days binding for me despite the what the agreement says?
Yes. But there's an option for a shorter period be agreement.
Your lease suggests your landlord may agree to a shorter notice. So ask them.