The gap Redis 6 shipped CLIENT TRACKING in 2020: opt a connection in, and the server pushes an invalidation the moment a key you've read changes anywhere. It's the building block for a correct client-side cache — no TTL guessing, no serving stale data because nobody told you it changed. StackExchange.Redis never implemented it. The issue has been open since 2020([#1461( https://github.com/StackExchange/StackExchange.Redis/issues/1461) ), and the 3.x rewrite still ships without it. ...