Mobile substrate (now called cydiasubstrate) has been updated and released for the ios7 jailbreakers. With this, developers can now start compiling and testing their tweaks on arm64 devices such as the iphone 5s. Every tweak will need to at least be recompiled for arm64 support. Something like sbsettings needs a full recompile plus every toggle needs to be recompiled. Several tweaks still aren’t ready. If a tweak does not support arm64 on your 5s type device, it simply wont load or do anything.

Developers wanting to upgrade their tweaks to ios7 can follow this awesome guide. You need a MAC running xcode 4.4 and xcode 5.0.2: http://iphonedevwiki.net/index.php/Updating_extensions_for_iOS_7