It's been a while since there's been a significant feature update for Windows 10 IoT Core. The most recent one is the October 2018 Update, so it's well over a year old. As it turns out, Microsoft might be working on something new. According to a job listing on LinkedIn (spotted by Windows Latest), Microsoft is looking for an engineer to help build its new IoT OS, which will be based on Windows 10X.
Specifically, the listing reads, "You will build the next generation IoT operating system based on Windows 10X." It's more likely that rather than Windows 10X, the company is talking about Windows Core OS, which is the sort of backbone behind Windows 10X, the OS that's going to run on the Surface Neo and other dual-screen devices.
An IoT variant would be a different version of Windows Core OS, or something with a different shell if it even has a shell at all. In fact, this strategy is what you'd expect from Windows 10 IoT Core.
Naturally, there's no clue as to when this will ship, since it's something that's still in development. Maybe we'll hear more about it when Windows 10X launches.