"Is this a function that needs to be addressed by a Quicken update?"
No.
It's up to your financial institution to elect to provide downloads to Quicken (and .CSV downloads don't count). Your financial institution must also choose which accounts they provide downloads for.
Not all financial institutions provide Quicken downloads. And those financial institutions that provide downloads do not necessarily provide downloads for all their account types.
"I have it set up like a 529 account but Quicken won't connect with my brokerage to update the account because it's not really a 529."
Not only will your financial institution have to choose to provide downloads for your account; but your financial institution will have to choose an account type recognized by Quicken and to format their download in the appropriate format for that account type.
Bottom line: talk to your financial institution.