The Galaxy Note 8 is approaching its end-of-life phase as Samsung downgrades its update cycle. Instead of monthly updates, the handset will receive quarterly ones. The Note 8 has been around for three years, so this news isn't surprising. The phone joins the Galaxy S8 series in this demotion into quarterly security updates.
Note 8 owners can expect to receive patches and updates quarterly until October 2021, at least. After that date, it'll be up to Samsung to send over any fixes for significant security flaws or known exploits. So, if you're still hanging on to your Note 8, remember that this end-of-life phase has begun.
Source: 9to5Google