Update CCA migration instructions

public/wiki/cardinal-components-api/upgrade-instructions/CCA-6-changes.md

@@ -12,18 +12,34 @@ The root package has changed from `dev.onyxstudios` to `org.ladysnake`.
 You can migrate quickly by using your IDE's global search feature - here are the instructions for Intellij Idea:
 
 1. press <kbd><kbd>Ctrl</kbd> + <kbd>Shift</kbd> + <kbd>R</kbd></kbd> (or <kbd><kbd>Cmd</kbd> + <kbd>Shift</kbd> + <kbd>R</kbd></kbd> on MacOS) to open the global replace window
+   - make sure the "Regex" option (the `.*` button to the right of the search field) is *disabled*
 2. type `import dev.onyxstudios.cca` in the first line ("Search")
 3. type `import org.ladysnake.cca` in the second line ("Replace")
 4. Click on <samp>Replace All</samp> to perform the replacement
 5. You're done!
 
 ## Changes to the Base module
 
-- AutoSyncedComponent
+`AutoSyncedComponent` now reads from and writes to a `RegistryByteBuf` instead of a `PacketByteBuf`.
+This new type can be used in exactly the same way, while also allowing to use more vanilla serialization methods.
+You can use the same Search/Replace procedure as above to handle this migration, first replacing `public void writeSyncPacket(PacketByteBuf` with `public void writeSyncPacket(RegistryByteBuf`,
+then replacing `public void applySyncPacket(PacketByteBuf` with `public void applySyncPacket(RegistryByteBuf`.
 
-## Changes to the Entity module
+## Changes to the Item module
+
+With Minecraft 1.20.5 adding data components for item stacks,
+all the functionality of the `cardinal-components-item` module has been superseded by vanilla components and Fabric API's [API Lookup API](https://github.com/FabricMC/fabric/blob/1.20.5/fabric-api-lookup-api-v1/README.md).
+As such, **item components have been entirely removed from Cardinal Components API.**
 
-- Removal of `PlayerCopyCallback`
+You can find an example of a component interface reimplemented with the new APIs in [CCA's test mod](https://github.com/Ladysnake/Cardinal-Components-API/blob/1.20.5/src/testmod/java/org/ladysnake/componenttest/content/vita/ItemVita.java).
+The basic idea is:
+1. move all your component's fields to an immutable record
+2. create a `Codec`, a `PacketCodec` and a `DataComponentType` for that record
+3. register the `DataComponentType` to `Registries.DATA_COMPONENT_TYPE`
+4. reimplement your component interface by delegating reads and writes to the new data component, using `ItemStack#get`, `ItemStack#set`, and `ItemStack#apply` as required
+5. register an `ItemApiLookup<T, Void>` for your component interface
+6. replace uses of `COMPONENT_KEY.get(stack)` with `API_LOOKUP.get(stack, null)`
 
-## Removal of the Item module
+## Changes to the Entity module
 
+The `PlayerCopyCallback` has been removed. If you were using it, you can switch to `ServerPlayerEvents.COPY_FROM` from Fabric API.