You're right, my bad - https://3ds.guide/cart-update.html I thought cart updates just missed the browser but 3ds sound isn't updated either.Look here https://3ds.guide/get-started-(old-3ds) it says that soundhax will not work if you cart update to a higher fw and that you need an alternative method to launch the homebrew launcher
Depending on resources - CN - or cart update to 4.5-6.0 for mset might be better