diff --git a/app/node-backend/README.md b/app/node-backend/README.md
new file mode 100644
index 0000000..15f6bf2
--- /dev/null
+++ b/app/node-backend/README.md
@@ -0,0 +1,39 @@
+# node-backend
+
+## Usage
+
+### With Docker
+
+1. Make sure Docker is installed on your system.
+2. Navigate to the ``/WebMLOpenEO/app/node-backend`` in your terminal.
+3. Run the following command to build the Docker image:
+   ```bash
+   docker build -t node-backend .
+4. Run the following command to run the application:
+    ```bash
+    docker run -p 3000:3000 --name node-backend node-backend
+### Without Docker
+
+1. Make sure node.js is installed on your system.
+2. Navigate to ``/WebMLOpenEO/app/node-backend`` in your terminal.
+3. Run the following command to install all dependencies:
+   ```bash
+   npm install
+3. Run the following command to run the application:
+
+   ```bash
+   npm start
+
+## Testing
+
+1. Make sure node.js is installed on your system.
+2. Navigate to ``/WebMLOpenEO/app/node-backend`` in your terminal.
+3. Run the following command to install all dependencies:
+   ```bash
+   npm install
+3. Run the following command to test the application:
+
+   ```bash
+   npm test
+
+> Attention! As this app is heavily dependent on the R-backend, 6 out of 14 tests will fail if the R-backend is not accessible. To start it, please refer to its README.
\ No newline at end of file
diff --git a/app/node-backend/validation_schemes/classify_further_details.js b/app/node-backend/validation_schemes/classify_further_details.js
index 60cd9e7..b7cfc76 100644
--- a/app/node-backend/validation_schemes/classify_further_details.js
+++ b/app/node-backend/validation_schemes/classify_further_details.js
@@ -108,10 +108,12 @@ function validate_CRS(feature_collection)
     // Proj4-Definition for Web Mercator (EPSG:3857)
     const webMercatorDef = proj4.defs('EPSG:3857');
 
-    // add more CRS and alias then proj4-default:
+    // add more CRS and alias then proj4-default: 
+    // TODO: Any CRS or alias could simply be added here.
     proj4.defs('urn:ogc:def:crs:EPSG:3857', proj4.defs('EPSG:3857'));
     proj4.defs('urn:ogc:def:crs:EPSG:4326', proj4.defs('EPSG:4326'));
     proj4.defs('urn:ogc:def:crs:OGC:1.3:CRS84', proj4.defs('EPSG:4326'));
+    proj4.defs('urn:ogc:def:crs:OGC::CRS84', proj4.defs('EPSG:4326'));
 
     // lookup sourceCRS
     const sourceCRS = proj4.defs(feature_collection.crs.properties.name);
diff --git a/app/node-backend/validation_schemes/classify_schemas.js b/app/node-backend/validation_schemes/classify_schemas.js
index ec58db1..9d7d780 100644
--- a/app/node-backend/validation_schemes/classify_schemas.js
+++ b/app/node-backend/validation_schemes/classify_schemas.js
@@ -100,7 +100,8 @@ const validCRS = [
   'EPSG:102113',
   'urn:ogc:def:crs:EPSG:3857',
   'urn:ogc:def:crs:EPSG:4326',
-  'urn:ogc:def:crs:OGC:1.3:CRS84'
+  'urn:ogc:def:crs:OGC:1.3:CRS84',
+  'urn:ogc:def:crs:OGC::CRS84'
 ];
 
 const CRS_SCHEMA = JOI.object(