Microsoft added quality improvements to the servicing stack for Windows 10 version 1703, the component designed to install Windows updates.
In this update's description, Microsoft also recommends Windows 10 users to first update the servicing stack to the latest version before trying to install the latest cumulative updates for their operating system.
Installing servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft security fixes.

Update can be installed via Windows Update or the Microsoft Update Catalog
According to Microsoft, the servicing stack update also "contains the "component-based servicing stack" (CBS), which is a key underlying component for several elements of Windows deployment, such as DISM, SFC, changing Windows features or roles, and repairing components."
The servicing stack update can be installed automatically via Windows Update or using a standalone update package users can download from the Microsoft Update Catalog website.
Windows Server (Windows Server, Windows Server 2016, Windows Server 2012 R2, or Windows Server 2012) users can also employ the Windows Server Update Services (WSUS) to deploy the update to all computers on the network.
Servicing stack update mandatory to avoid update issues
Users are also advised to update the servicing stack to the latest version as soon as possible to avoid experiencing potential issues during the installation process of feature and quality updates.
Microsoft states that "If you don't install the latest servicing stack update, there's a risk that your device can't be updated with the latest Microsoft security fixes."
Installation notes

  • Servicing stack updates contain the full servicing stack; as a result, typically administrators only need to install the latest servicing stack update for the operating system.
  • Installing servicing stack update does not require restarting the device, so installation should not be disruptive.
  • Servicing stack update releases are specific to the operating system version (build number), much like quality updates.
  • Search to install latest available Servicing stack update for Windows 10.