My needs are very simple - can I start using CI4?

You should know, though, that if you do build on CI4, it's always possible we'll refactor something that will break your site and cause you extra work, so there's that. And security issues that might be found, etc. So - it's possible, but can't really recommend it.

First, Lonnie, your effort on CI4 is much appreciated.

I've extended (or more, hacked) CI3 somewhat for our company platform and was positively surprised that most random edge cases have made it to CI4, sometimes very close to my own implementation - so to say that I'm excited to have a lot of it come straight out of the box is understatement.

There's difference when you know you definitely want to change something, and when you know the core is there and just needs some polish, so we don't expect is all I personally was after, as I am quite keen on learning the new version now and get a bit of a head start.

Keep up the good work and see you the other side!