Any rent-increase notice given on or after 6 September when the permitted rate is 0% has no effect. 25. In consequence of the new section 21A of the 2016 Act imposing a rent cap, sub- paragraph (6) modifies section 22 of the 2016 Act providing that any rent increase agreed between a landlord and tenant has no effect to the extent that the increase is more than the permitted rate. 26.