Add two release parameters

README.md

@@ -100,3 +100,12 @@ docker build -t nextcloud-client-win32:<version> client/admin/win/docker/
 ```bash
 docker run -v "$PWD:/home/user/" nextcloud-client-win32:2.2.2 /home/user/win/build.sh $(id -u)
 ```
+
+## Building a release
+
+When we build releases there are two additional cmake parameters to consider:
+
+* `-DMIRALL_VERSION_SUFFIX=<STRING>`: for a generic suffix name such as `beta` or `rc1`
+* `-DMIRALL_VERSION_BUILD=<INT>`: an internal build number. Should be strickly increasing. This allows update detection from `rc` to `final`
+
+Note that this had mostly usage on Windows and OS X. On linux the package manager will take care of all this.