Update README

README.md

@@ -19,7 +19,7 @@ brew install wavpack
 ```
 
 For Linux and Windows, the package comes with pre-built binaries of the most 
-[recent version Wavpack verison](https://github.com/dbry/WavPack/releases/tag/5.7.0).
+[recent version Wavpack version](https://github.com/dbry/WavPack/releases/tag/5.7.0).
 
 On Linux, if an existing `wavpack` installation is found, the package will use it. Otherwise, it will use the pre-built binaries available in the `wavpack_numcodecs/libraries` folder.
 
@@ -59,4 +59,18 @@ Available `**kwargs` can be browsed with: `WavPack?`
 
 **NOTE:** 
 In order to reload in zarr an array saved with the `WavPack`, you just need to have the `wavpack_numcodecs` package
-installed.
+installed.
+
+# Developmers guide
+
+## How to upgrade WavPack installation
+
+To upgrade the WavPack installation, you need to:
+
+1. Download the latest version of WavPack from the [official website](https://www.wavpack.com/downloads.html).
+2. Extract the content of the downloaded file.
+3. Create a new folder in the `src/wavpack_numcodecs/libraries` folder with the name of the version of the WavPack you are installing.
+4. Add the Windows .dll and .lib files to the `windows-x86_32` and `windows-x86_64` folders, respectievely.
+5. Build the Linux shared library and copy the `.so` file to the `linux-x86_64` folder.
+6. Set the `LATET_WAVPACK_VERSION` variable in the `setup.py` to match the version of the WavPack you are installing.
+7. Update the version of the CI workflows in the `.github/workflows/` folder.