Today, Microsoft released Windows 10 Insider Preview build 17754 to the Slow ring. As we're approaching the end of the Redstone 5 development cycle, builds are coming more frequently, for both the Fast ring and the Slow ring. This build replaces build 17744.1004, which was made available just four days ago. That's a serviced version of build 17744, which arrived on August 30.
Since build 17744 arrived, there have been several new builds. Microsoft doesn't do Slow ring changelogs, so here are the changelogs from the ones that were released:
The Windows 10 October 2018 Update will, as its name suggests, arrive for the general public next month. That means that we should be seeing an RTM build for version 1809 very soon, possibly even next week. Once that hits the Fast ring, it will then move to the Slow ring, and eventually to the Release Preview ring in preparation for its release.
After that, Insiders will move on to testing the next version, which is codenamed 19H1. Currently, that's already in testing with the Skip Ahead subset of the Fast ring.