You'll see the following warning message in H&R Block’s 2018 tax software if, you indicated on your return that you're over the age of 71 and you entered an RRSP contribution amount on the Schedule 7: Contributions to RRSPs or any other retirement fund or account page:
You can't contribute to an RRSP if you're over 71. [Warning]
How do I fix this?
You can check your date of birth entry on the Your personal information page under the ABOUT YOU icon on the GET STARTED tab. If you want to remove the RRSP contributions from your return, go to the QUICK SLIP page under the QUICK ENTRY tab, and click the Delete link next to the RRSP contributions you entered.
The Canada Revenue Agency (CRA) says that the last day you can contribute to your RRSPs is December 31 of the year you turn 71. After which, you must either withdraw your RRSP, transfer your RRSP to a RRIF, or use your RRSP to purchase an annuity.