You could eventually participate to the Canadian investment immigration programs. We are lacking information from you to guide you properly, but basically I would encourage you to contact a Canadian lawyer who can assist you in the process because this is a serious issue that must be addressed ab initio. Just to share a similar experience we had about five years ago: We did have a QIIP (Quebec Immigrant Investor Program) client who had not disclosed to us a DUI infraction leading to accidental death as a young adult 20-plus years before. The Canadian federal authorities initially refused the application, but we managed to have delivered permanent residence after having this refusal challenged in court. If we had been told earlier it would have been easier and a less stressful process for this client, so I encourage you to do the same with your Canadian attorney.
What is the standard for background checks in the Canadian investment immigration programs?
I am from a developing country and have a criminal conviction from about 20 years ago. I have not done anything since then. Will I be restricted from participating in the program? What can I do to increase my chances to be allowed to participate?
Seems like there are two questions here. One, criminal background checks are expected for any place you've lived for more than six months. Two, depending on the nature of the crime, it could be an issue. Conventionally, a completed sentence from 10-plus years ago is "deemed rehabilitated" in the eyes of the Canadian government.