@ScrappyCanada @garlicmonger This page (https://www.sunlife.ca/en/investments/rrsp/contribution-limit/) says: "Contributions made in the first 60 days of the year can be used towards the previous year’s or current year’s contribution amount."
I found some info here (https://www.moneysense.ca/save/investing/rrsp/how-do-the-rrsp-contribution-carry-forward-rules-work/) which also seems relevant to this topic but still, unfortunately, a little ambiguous:
You have up until March 1, 2024, to contribute to your RRSP for the 2023 tax year. As stated above, when you file your 2022 tax return, you will get the 2023 RRSP room that becomes available back to Jan. 1, 2023.
Interestingly, if you make your 2023 RRSP contribution in early 2023 based on your estimated new RRSP room, even though you cannot deduct it until next year, you may have to claim it on your 2022 tax return. This is because you claim RRSP contributions when made, even if they are not deducted until a future year.