Clause 7 is in consequence to a change in the number of polling days. They are transitional provisions with respect to the reporting of third parties. After clause 6 comes into force and the repeal of part 22, it would allow for the transition from the three-day polling period back to a one-day polling period after Bill C-19 is no longer in effect.
On June 17th, 2021. See this statement in context.