OEMs have received the new version ahead of time to put the latest version of Windows 10 on devices.
Usually, requirements don't change between different feature updates, but Windows 10 version 2004 is special. Microsoft is making available 64-bit builds only to OEMs which in turn means that OEMs cannot offer 32-bit versions of Windows 10 anymore on their devices.
Microsoft notes on the Minimum Hardware Requirements Overview page on its Docs website:
Beginning with Windows 10, version 2004, all new Windows 10 systems will be required to use 64-bit builds and Microsoft will no longer release 32-bit builds for OEM distribution. This does not impact 32-bit customer systems that are manufactured with earlier versions of Windows 10; Microsoft remains committed to providing feature and security updates on these devices, including continued 32-bit media availability in non-OEM channels to support various upgrade installation scenarios.
The change is not as drastic as it sounds as the vast majority of new PCs comes with 64-bit versions of Windows 10 already. In fact, you will be hard pressed finding a 32-bit Windows 10 PC when you shop for a new personal computer. Other distribution channels are not affected by the change. In other words: devices with 32-bit versions of Windows 10 will continue to receive updates just like before.
Hardware requirements for Windows 10 version 2004 are still listed for 32-bit and 64-bit versions of the operating system. RAM requirements are still 1 Gigabyte or more for 32-bit systems and 2 Gigabytes or more for 64-bit systems. Microsoft introduced a storage requirements change in Windows 10 version 1903 by increasing the minimum storage capacity for 32-bit and 64-bit versions of Windows 10 to 32 Gigabytes.
Previously, 32-bit versions required 16 Gigabytes of storage while 64-bit versions 20 Gigabytes of storage.
The change is a small step in phasing out 32-bit versions of Windows altogether. Microsoft has not revealed any plans in this regard though at the time of writing.
Windows 10 users may check the system type of the operating system under Settings > System > About.