I don’t think csis ever provided actual notes, usually it’s just a generic letter saying your notes are exemption , but they stopped sending even those some time ago
CBSA can provide entry-exit information which is VERY helpful for physical presence, and will also provide the full IRCC gcms notes for citizenship apps. While the underlying data (the system notes) are the same, CBSA and IRCC do not always 'redact' (exempt from disclosure to you) the info identically - i.e. you might get a tiny bit more info (more like the metadata than the info itself, really). Whether that small difference is useful to you or not is a different question.