The new default cache size as of January 25, 2017 is 20GB, up from the standard default of 5GB. This is to accommodate larger application installers that are often above 10GBs. No action is necessary to receive the new default of 20GB. However, if you'd like to change the cache size to something else (perhaps smaller if you have small SSDs), you can do so by creating a custom client settings package in the SCCM console.
From the left sidebar select Administration->Client Settings. Right-click and select "Create Custom Client Device Settings".
Check the box next to "Client Cache Settings" at the bottom of the list.
Deploy the new client settings by right-clicking and selecting Deploy. Select a target collection. The client will receive the new client settings next time they check-in with the SCCM server.