Last Thursday, Microsoft released Windows 10 for PCs build 15048 to the Fast ring, so today, it's moving on to the Slow ring. While the Fast ring is usually weekly and the Slow ring is typically monthly, that hasn't been the case as of late.
PCs on the Slow ring haven't seen a new build since 14986 was offered in mid-December. Windows 10 Mobile users had to wait even longer since 14965 was released in November, and was the only Creators Update preview in the Slow ring for phones until 15043 was offered last week.
While build 15048 didn't include any new front-facing features for Fast ring Insiders, there's quite a bit that you'll find as a Slow ring user, since it's been so long since you've seen a new build. You can now buy ebooks from the Windows Store and read them in the Edge browser, there are various gaming improvements, such as the new Game Mode, and of course, there are other improvements to Edge, Cortana, Settings, and the rest of the OS.
If you're on the Slow ring, you can install today's build by heading over to Settings -> Update & security -> Windows update. If not, go to the Windows Insider Program tab and click 'Get started'. When your PC reboots, go back and make sure you're set to the Slow ring.