<edit> Question has been comprehensively answered. Thank you all.
I'm preparing the SIs for our club winter race series, beginning in November and ending in April.
Should we conduct races in November and December under RRS 2017-2020 and races in January to April under RRS 2021-2024?
Is it permissible to complete the series under RRS 2017-2020 and switch to the new rules for the Spring / Summer Series?
If this has already been covered somewhere here I can't find it, not can I find any guidance from World Sailing or US Sailing.
I'm sure I'm not the only person in this situation.
Many thanks in advance.