I had a 3.3U Wii, and updated to 4.0 today to be the guinea pig and see what changes happen if you update. So I'm posting my findings here. If you update to 4.0: 1.You WILL NOT lose your current Homebrew Channel. 2.You WILL lose the ability to install the Homebrew Channel with any version of the Twilight Hack if you don't already have the homebrew channel installed. 3. Softmods and DVDX SHOULD still work. I haven't tested this myself as I have a modchip, but the IOS's which make this work have not been patched as far as I know. (If anyone else can personally confirm their softmod still works, let me know. EDIT: Wii softmod/backup confirmed to work, no word on Gamecube. 4. You will NOT lose your ability to install WADs if you have Waninko's cIOS. I've heard conflicting reports about this, but I have successfully installed WiiWare games onto the system menu and played them just fine. I simply used WAD Manager 1.3 and had a cIOS installed. IF YOU DO NOT HAVE WANINKOKO'S CIOS INSTALLED BEFORE UPDATING YOU WILL NO LONGER BE ABLE TO INSTALL WADS. Be sure to install this before updating if you decide to. You can find it: here. 5. You CAN play WiiWare/VC/Custom Channels you've installed via WAD Manager and play them via the SD Channel! (Thanks stev!) Once you update to 4.0, you must find a IOS60 file, patch it with freethebug, and then install it via wad manager. Once you have, use the "MOVE" option on the Wii to move the WAD over to the SD card, launch it, success! 6. You CAN downgrade from a 4.0 Wii if you already have a cIOS installed. Just use waninkoko's cIOS downgrader. I have personally gone from 3.3U, to 4.0U and back to 3.2U successfully. All that is required is that you have the a cIOS installed BEFORE upgrading to 4.0U. You can find the latest one here. Just install this before upgrading and you should be able to update to 4.0U with your wad installing abilities intact and be able to downgrade to 3.2U if you wish. 7. This does NOT affect modchips at all. There ya go, it's what I know so far. Anyone else post their findings and personal experience here.