Microsoft has started shipping builds from a new release called Redstone 5 lab so naturally, Redstone 4 builds are done. After releasing a series of Builds starting from 17120 frequently, Microsoft looks to be closing on Build 17133 which would be the public release.
After releasing 17133 on Fast Ring last week, Microsoft released 17133 in the Slow ring too on Friday. However, Microsoft said they would be slow in deploying it to the machines enrolled in the Same ring.
It is expected that Build 17133 would be deployed to Release preview ring by this week and to global release on 10th April 2018.
You can read more about the build here: