I don't think anything much has changed, and the only result is tightening the business rules. Two codifed bits of CASL are similar to guidelines and regs in other countries:
• Responses to a current customer, or someone who has inquired in the last six months.
• Messages that provide information about a purchase, subscription, membership, account, loan, or other ongoing relationship, including delivery of product updates or upgrades.
So, you may already have noticed they bug you a lot every once in a while, to check your account settings, etc. That's to get you to come to the site, manage your account, and they call that an ongoing relationship. Make sure that's at least every 6 months and you are within the letter of the law. Probably.

Charities have a specific exemption. This may not be the exact wording of the law as I am using a general reference. I am not a laywer, so check with yours:
"Messages sent on behalf of a charity or political organization for the purposes of raising funds or soliciting contributions."
There are some others as well that might allow you to say, disclose where you got their name from, etc.