Forgotten IT3 submission

I've already submitted my IRP5 but I just found IT3 for an investment policy from last year and this year. Is it possible to still submit these or should I wait for the next tax window next year? What are the implications of this cause I don't want to discover that I own the tax man anything by failing this submission.

You can navigate to your Tax Return in the history section of your SARS eFiling profile and "request for correction". You can then resubmit and include this additional tax certificate.