Starting with Android 15, Google’s operating system requires at least 32 GB of flash memory for smartphones that have a set of Google Mobile Services (GMS) applications and services pre-installed.
Of these 32 GB, at least 75% should be allocated to the data partition, which stores pre-installed system applications, system application data, certain system files, and all user applications and files.
The previous limit of 16 GB was introduced with the release of Android 13, and before that it was 8 GB. Please note that a smartphone with less than 32 GB of memory cannot be upgraded to Android 15 if it was released on an earlier version.
Fortunately, there aren’t many devices with 16 GB or 32 GB of internal storage right now, and it goes without saying that your experience using a device with 32 GB of storage will be terrible, regardless of whether it’s Android 15 or not. But it’s interesting to see that Google has a real minimum storage size that it sets for those devices that need GMS.
The same goes for RAM. Devices with 2 GB and 3 GB of RAM should use Android Go Edition, a special version of the system designed for devices with frankly weak hardware, while devices with less than 2 GB of RAM cannot receive GMS at all.
Devices with 4 GB of RAM on board can still receive GMS and run the full version of Android 15, but starting with Android 16 they will also have to follow the path of Android Go, meaning that the full version of Android will have a minimum RAM requirement of 6 GB.
P.S. For up-to-date news on the Xiaomi HyperOS proprietary system, as well as detailed instructions and recommendations for configuring it, see this section.