That's right, it's now at version 21, from what I've read it doesn't add anything special, just IOS62 and the Wii U Transfer Tool (found for free in the Shop Channel). These 2 new add-ons are used to transfer your game saves, WiiWare, Virtual Console and others Channels downloaded in the Shop Channel, over to your WiiU (if you're lucky enough to have one :p)
Anyway I updated using Multi-Mod Manager's channel manager so I didn't have to do my whole system or mess around installing wads :)
How to update your Shop Channel:
1) Open Multi-Mod Manager 13.4
2) Go to "Load another IOS" and choose IOS-236
3) Go to "Manage Wii Channels"
4) Press right until it says Shop Channel then press down and press right to select your region
5) Press A and wait....this might take a few minutes. If you do it right the end result will look like this:
Getting Content 18/18
Installing, please wait................
Shop Channel successfully installed!
Press any button to continue.
6) Press Home, then Home again and one last time to exit to the Wii menu. Load the Shop Channel and enjoy buying WiiWare games, Channels, and your favorite classic games again while still having your Softmod 100% intact.
Happy gaming everyone :)
It should be noted IOS62 will not be installed If you update the way I detailed above as it is actually added by the "System Update" function and is not part of the Shop Channel. As of today (November 13th) you can download IOS62 separately via NUS Downloader or ModMii and install it with Multi-Mod Manager.