diff --git a/README.md b/README.md
index 691e4027..2c56cb07 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ JavaScript client for the openEO API.
 
 [![Build Status](https://travis-ci.org/Open-EO/openeo-js-client.svg?branch=master)](https://travis-ci.org/Open-EO/openeo-js-client)
 
-This client is in **version 0.3.0** and supports **openEO API versions 0.3.0 and 0.3.1**. Legacy versions are available as releases.
+This client is in **version 0.3.1** and supports **openEO API versions 0.3.0 and 0.3.1**. Legacy versions are available as releases.
 
 ## Usage
 This library can run in a recent browser supporting ECMAScript 2015 or node.js.
diff --git a/openeo.js b/openeo.js
index a5e2f80a..31f19789 100644
--- a/openeo.js
+++ b/openeo.js
@@ -42,30 +42,30 @@ class OpenEO {
 
 class Connection {
 	constructor(baseUrl) {
-		this._baseUrl = baseUrl;
-		this._userId = null;
-		this._token = null;
-		this._subscriptions = new Subscriptions(this);
-		this._capabilitiesCache = null;
+		this.baseUrl = baseUrl;
+		this.userId = null;
+		this.accessToken = null;
+		this.capabilitiesObject = null;
+		this.subscriptionsObject = new Subscriptions(this);
 	}
 
 	getBaseUrl() {
-		return this._baseUrl;
+		return this.baseUrl;
 	}
 
 	getUserId() {
-		return this._userId;
+		return this.userId;
 	}
 
 	capabilities() {
-		if (this._capabilitiesCache === null) {
+		if (this.capabilitiesObject === null) {
 			return this._get('/').then(response => {
-				this._capabilitiesCache = new Capabilities(response.data);
-				return this._capabilitiesCache;
+				this.capabilitiesObject = new Capabilities(response.data);
+				return this.capabilitiesObject;
 			});
 		}
 		else {
-			return Promise.resolve(this._capabilitiesCache);
+			return Promise.resolve(this.capabilitiesObject);
 		}
 	}
 
@@ -121,8 +121,8 @@ class Connection {
 			if (!response.data.access_token) {
 				throw new Error("No access_token returned.");
 			}
-			this._userId = response.data.user_id;
-			this._token = response.data.access_token;
+			this.userId = response.data.user_id;
+			this.accessToken = response.data.access_token;
 			return response.data;
 		}).catch(error => {
 			this._resetAuth();
@@ -137,22 +137,22 @@ class Connection {
 
 	listFiles(userId = null) {  // userId defaults to authenticated user
 		if(userId === null) {
-			if(this._userId === null) {
+			if(this.userId === null) {
 				return Promise.reject(new Error("Parameter 'userId' not specified and no default value available because user is not logged in."));
 			} else {
-				userId = this._userId;
+				userId = this.userId;
 			}
 		}
 		return this._get('/files/' + userId)
-			.then(response => response.data.files.map((f) => new File(this, userId, f.name)._addMetadata(f)));
+			.then(response => response.data.files.map((f) => new File(this, userId, f.name).setAll(f)));
 	}
 
 	createFile(name, userId = null) {  // userId defaults to authenticated user
 		if(userId === null) {
-			if(this._userId === null) {
+			if(this.userId === null) {
 				return Promise.reject(new Error("Parameter 'userId' not specified and no default value available because user is not logged in."));
 			} else {
-				userId = this._userId;
+				userId = this.userId;
 			}
 		}
 		return Promise.resolve(new File(this, userId, name));
@@ -160,18 +160,27 @@ class Connection {
 
 	validateProcessGraph(processGraph) {
 		return this._post('/validation', {process_graph: processGraph})
-			.then(_ => [true, {}]) // Accepts other status codes than 204, which is not strictly following the spec
+			.then(() => [true, {}]) // Accepts other status codes than 204, which is not strictly following the spec
 			.catch(error => [false, error.response.data]);
 	}
 
 	listProcessGraphs() {
 		return this._get('/process_graphs')
-			.then(response => response.data.process_graphs.map((pg) => new ProcessGraph(this, pg.process_graph_id)._addMetadata(pg)));
+			.then(response => response.data.process_graphs.map((pg) => new ProcessGraph(this, pg.process_graph_id).setAll(pg)));
 	}
 
 	createProcessGraph(processGraph, title = null, description = null) {
-		return this._post('/process_graphs', {title: title, description: description, process_graph: processGraph})
-			.then(response => new ProcessGraph(this, response.headers['OpenEO-Identifier'] || response.headers['openeo-identifier'])._addMetadata({title: title, description: description}));
+		var pgObject = {title: title, description: description, process_graph: processGraph};
+		return this._post('/process_graphs', pgObject)
+			.then(response => new ProcessGraph(this, response.headers['openeo-identifier']).setAll(pgObject))
+			.then(pg => {
+				if (this.capabilitiesObject.hasFeature('describeProcessGraph')) {
+					return pg.describeProcessGraph();
+				}
+				else {
+					return Promise.resolve(pg);
+				}
+			});
 	}
 
 	execute(processGraph, outputFormat = null, outputParameters = {}, budget = null) {
@@ -191,7 +200,7 @@ class Connection {
 
 	listJobs() {
 		return this._get('/jobs')
-			.then(response => response.data.jobs.map(j => new Job(this, j.job_id)._addMetadata(j)));
+			.then(response => response.data.jobs.map(j => new Job(this, j.job_id).setAll(j)));
 	}
 
 	createJob(processGraph, outputFormat = null, outputParameters = {}, title = null, description = null, plan = null, budget = null, additional = {}) {
@@ -209,12 +218,20 @@ class Connection {
 			};
 		}
 		return this._post('/jobs', jobObject)
-			.then(response => new Job(this, response.headers['OpenEO-Identifier'] || response.headers['openeo-identifier'])._addMetadata({title: title, description: description}));
+			.then(response => new Job(this, response.headers['openeo-identifier']).setAll(jobObject))
+			.then(job => {
+				if (this.capabilitiesObject.hasFeature('describeJob')) {
+					return job.describeJob();
+				}
+				else {
+					return Promise.resolve(job);
+				}
+			});
 	}
 
 	listServices() {
 		return this._get('/services')
-			.then(response => response.data.services.map((s) => new Service(this, s.service_id)._addMetadata(s)));
+			.then(response => response.data.services.map((s) => new Service(this, s.service_id).setAll(s)));
 	}
 
 	createService(processGraph, type, title = null, description = null, enabled = true, parameters = {}, plan = null, budget = null) {
@@ -229,7 +246,15 @@ class Connection {
 			budget: budget
 		};
 		return this._post('/services', serviceObject)
-			.then(response => new Service(this, response.headers['OpenEO-Identifier'] || response.headers['openeo-identifier'])._addMetadata({title: title, description: description}));
+			.then(response => new Service(this, response.headers['openeo-identifier']).setAll(serviceObject))
+			.then(service => {
+				if (this.capabilitiesObject.hasFeature('describeService')) {
+					return service.describeService();
+				}
+				else {
+					return Promise.resolve(service);
+				}
+			});
 	}
 
 	_get(path, query, responseType) {
@@ -261,15 +286,6 @@ class Connection {
 		});
 	}
 
-	_put(path, body, contenttype = undefined) {
-		return this._send({
-			method: 'put',
-			url: path,
-			data: body,
-			headers: (contenttype == undefined ? {} : { 'content-type': contenttype })
-		});
-	}
-
 	_delete(path) {
 		return this._send({
 			method: 'delete',
@@ -290,13 +306,13 @@ class Connection {
 	}
 
 	_send(options) {
-		options.baseURL = this._baseUrl;
+		options.baseURL = this.baseUrl;
 		if (this.isLoggedIn() && (typeof options.withCredentials === 'undefined' || options.withCredentials === true)) {
 			options.withCredentials = true;
 			if (!options.headers) {
 				options.headers = {};
 			}
-			options.headers['Authorization'] = 'Bearer ' + this._token;
+			options.headers['Authorization'] = 'Bearer ' + this.accessToken;
 		}
 		if (options.responseType == 'stream' && !isNode) {
 			options.responseType = 'blob';
@@ -304,25 +320,32 @@ class Connection {
 		if (!options.responseType) {
 			options.responseType = 'json';
 		}
+		switch(options.method) {
+			case 'put':
+			case 'patch':
+			case 'delete':
+				options.validateStatus = status => status == 204;
+				break;
+		}
 
 		return axios(options);
 	}
 
 	_resetAuth() {
-		this._userId = null;
-		this._token = null;
+		this.userId = null;
+		this.accessToken = null;
 	}
 
 	isLoggedIn() {
-		return (this._token !== null);
+		return (this.accessToken !== null);
 	}
 
 	subscribe(topic, parameters, callback) {
-		return this._subscriptions.subscribe(topic, parameters, callback);
+		return this.subscriptionsObject.subscribe(topic, parameters, callback);
 	}
 
 	unsubscribe(topic, parameters, callback) {
-		return this._subscriptions.unsubscribe(topic, parameters, callback);
+		return this.subscriptionsObject.unsubscribe(topic, parameters, callback);
 	}
 
 	_saveToFileNode(data, filename) {
@@ -421,7 +444,7 @@ class Subscriptions {
 	_createWebSocket() {
 		if (this.socket === null || this.socket.readyState === this.socket.CLOSING || this.socket.readyState === this.socket.CLOSED) {
 			this.messageQueue = [];
-			var url = this.httpConnection._baseUrl.replace('http', 'ws') + '/subscription';
+			var url = this.httpConnection.getBaseUrl().replace('http', 'ws') + '/subscription';
 
 			if (isNode) {
 				const WebSocket = require('ws');
@@ -485,7 +508,7 @@ class Subscriptions {
 
 	_sendMessage(topic, payload = null, priority = false) {
 		var obj = {
-			authorization: "Bearer " + this.httpConnection._token,
+			authorization: "Bearer " + this.httpConnection.accessToken,
 			message: {
 				topic: "openeo." + topic,
 				issued: (new Date()).toISOString()
@@ -553,7 +576,7 @@ class Capabilities {
 			authenticateBasic: 'GET /credentials/basic',
 			describeAccount: 'GET /me',
 			listFiles: 'GET /files/{user_id}',
-			validateProcessGraph: 'POST /validate',
+			validateProcessGraph: 'POST /validation',
 			createProcessGraph: 'POST /process_graphs',
 			listProcessGraphs: 'GET /process_graphs',
 			execute: 'POST /preview',
@@ -577,7 +600,9 @@ class Capabilities {
 			deleteProcessGraph: 'DELETE /process_graphs/{process_graph_id}',
 			describeService: 'GET /services/{service_id}',
 			updateService: 'PATCH /services/{service_id}',
-			deleteService: 'DELETE /services/{service_id}'
+			deleteService: 'DELETE /services/{service_id}',
+			subscribe: 'GET /subscription',
+			unsubscribe: 'GET /subscription'
 		};
 		
 		// regex-ify to allow custom parameter names
@@ -586,8 +611,7 @@ class Capabilities {
 		}
 
 		if (methodName === 'createFile') {
-			return true;   // Of course it's always possible to create "a (virtual) file".
-			// But maybe it would be smarter to return the value of hasFeature('uploadFile') instead, because that's what the user most likely wants to do
+			return this.hasFeature('uploadFile'); // createFile is always available, map it to uploadFile as it is more meaningful.
 		} else {
 			return this._data.endpoints
 				.map((e) => e.methods.map((method) => method + ' ' + e.path))
@@ -598,35 +622,71 @@ class Capabilities {
 	}
 
 	currency() {
-		return (this._data.billing ? this._data.billing.currency : undefined);
+		return (this._data.billing ? this._data.billing.currency : null);
 	}
 
 	listPlans() {
-		return (this._data.billing ? this._data.billing.plans : undefined);
+		return (this._data.billing ? this._data.billing.plans : null);
 	}
 }
 
 
-class File {
-	constructor(connection, userId, name) {
+class BaseEntity {
+
+	constructor(connection, properties = []) {
 		this.connection = connection;
-		this.userId = userId;
-		this.name = name;
+		this.clientNames = {};
+		this.extra = {};
+		for(var i in properties) {
+			var backend, client;
+			if (Array.isArray(properties[i])) {
+				backend = properties[i][0];
+				client = properties[i][1];
+			}
+			else {
+				backend = properties[i];
+				client = properties[i];
+			}
+			this.clientNames[backend] = client;
+			if (typeof this[client] === 'undefined') {
+				this[client] = null;
+			}
+		}
 	}
 
-	_addMetadata(metadata) {
-		// Metadata for files can be "size", "modified", or ANY (!) custom field name.
-		// To prevent overwriting of already existing data we therefore have to delete keys that already
-		// exist in "this" scope from the metadata object (if they exist)
-		delete metadata.connection;
-		delete metadata.userId;
-		delete metadata.name;
+	setAll(metadata) {
+		for (var name in metadata) {
+			if (typeof this.clientNames[name] === 'undefined') {
+				this.extra[name] = metadata[name];
+			}
+			else {
+				this[this.clientNames[name]] = metadata[name];
+			}
+		}
+		return this;
+	}
 
-		for(var md in metadata) {
-			this[md] = metadata[md];
+	getAll() {
+		var obj = {};
+		for (var backend in this.clientNames) {
+			var client = this.clientNames[backend];
+			obj[client] = this[client];
 		}
+		return Object.assign(obj, this.extra);
+	}
+
+	get(name) {
+		return typeof this.extra[name] !== 'undefined' ? this.extra[name] : null;
+	}
+
+}
 
-		return this;  // for chaining
+
+class File extends BaseEntity {
+	constructor(connection, userId, name) {
+		super(connection, ["name", "size", "modified"]);
+		this.userId = userId;
+		this.name = name;
 	}
 
 	// If target is null, returns promise with data as stream in node environment, blob in browser.
@@ -653,8 +713,39 @@ class File {
 		}
 	}
 
-	uploadFile(source) {
-		return this.connection._put('/files/' + this.userId + '/' + this.name, source, 'application/octet-stream');
+	_readFromFileNode(path) {
+		var fs = require('fs');
+		return fs.createReadStream(path);
+	}
+
+	// source for node must be a path to a file as string
+	// source for browsers must be an object from a file upload form
+	uploadFile(source, statusCallback = null) {
+		if (isNode) {
+			// Use a file stream for node
+			source = this._readFromFileNode(source);
+		}
+		// else: Just use the file object from the browser
+
+		var options = {
+			method: 'put',
+			url: '/files/' + this.userId + '/' + this.name,
+			data: source,
+			headers: {
+				'Content-Type': 'application/octet-stream'
+			}
+		};
+		if (typeof statusCallback === 'function') {
+			options.onUploadProgress = function(progressEvent) {
+				var percentCompleted = Math.round( (progressEvent.loaded * 100) / progressEvent.total );
+				statusCallback(percentCompleted);
+			};
+		}
+
+		// ToDo: We should set metadata here for convenience as in createJob etc., but the API gives no information.
+		return this.connection._send(options).then(() => {
+			return this;
+		});
 	}
 
 	deleteFile() {
@@ -663,37 +754,32 @@ class File {
 }
 
 
-class Job {
+class Job extends BaseEntity {
 	constructor(connection, jobId) {
-		this.connection = connection;
+		super(connection, [["job_id", "jobId"], "title", "description", ["process_graph", "processGraph"], "output", "status", "submitted", "updated", "plan", "costs", "budget"]);
 		this.jobId = jobId;
 	}
 
-	_addMetadata(metadata) {		
-		this.title       = metadata.title;
-		this.description = metadata.description;
-		this.status      = metadata.status;
-		this.submitted   = metadata.submitted;
-		this.updated     = metadata.updated;
-		this.plan        = metadata.plan;
-		this.costs       = metadata.costs;
-		this.budget      = metadata.budget;
-		return this;  // for chaining
-	}
-
 	describeJob() {
 		return this.connection._get('/jobs/' + this.jobId)
-			.then(response => response.data);
+			.then(response => this.setAll(response.data));
 	}
 
 	updateJob(parameters) {
 		return this.connection._patch('/jobs/' + this.jobId, parameters)
-			.then(response => response.status == 204);
+			.then(() => {
+				if (this.connection.capabilitiesObject.hasFeature('describeJob')) {
+					return this.describeJob();
+				}
+				else {
+					this.setAll(parameters);
+					return Promise.resolve(this);
+				}
+			});
 	}
 
 	deleteJob() {
-		return this.connection._delete('/jobs/' + this.jobId)
-			.then(response => response.status == 204);
+		return this.connection._delete('/jobs/' + this.jobId);
 	}
 
 	estimateJob() {
@@ -703,12 +789,26 @@ class Job {
 
 	startJob() {
 		return this.connection._post('/jobs/' + this.jobId + '/results', {})
-			.then(response => response.status == 202);
+			.then(() => {
+				if (this.connection.capabilitiesObject.hasFeature('describeJob')) {
+					return this.describeJob();
+				}
+				else {
+					return Promise.resolve(this);
+				}
+			});
 	}
 
 	stopJob() {
 		return this.connection._delete('/jobs/' + this.jobId + '/results')
-			.then(response => response.status == 204);
+			.then(() => {
+				if (this.connection.capabilitiesObject.hasFeature('describeJob')) {
+					return this.describeJob();
+				}
+				else {
+					return Promise.resolve(this);
+				}
+			});
 	}
 
 	listResults(type = 'json') {
@@ -757,67 +857,62 @@ class Job {
 }
 
 
-class ProcessGraph {
+class ProcessGraph extends BaseEntity {
 	constructor(connection, processGraphId) {
+		super(connection, [["process_graph_id", "processGraphId"], "title", "description", ["process_graph", "processGraph"]]);
 		this.connection = connection;
 		this.processGraphId = processGraphId;
 	}
 
-	_addMetadata(metadata) {
-		this.title = metadata.title;
-		this.description = metadata.description;
-		return this;  // for chaining
-	}
-
 	describeProcessGraph() {
 		return this.connection._get('/process_graphs/' + this.processGraphId)
-			.then(response => response.data);
+			.then(response => this.setAll(response.data));
 	}
 
 	updateProcessGraph(parameters) {
 		return this.connection._patch('/process_graphs/' + this.processGraphId, parameters)
-			.then(response => response.status == 204);
+			.then(() => {
+				if (this.connection.capabilitiesObject.hasFeature('describeProcessGraph')) {
+					return this.describeProcessGraph();
+				}
+				else {
+					this.setAll(parameters);
+					return Promise.resolve(this);
+				}
+			});
 	}
 
 	deleteProcessGraph() {
-		return this.connection._delete('/process_graphs/' + this.processGraphId)
-			.then(response => response.status == 204);
+		return this.connection._delete('/process_graphs/' + this.processGraphId);
 	}
 }
 
 
-class Service {
+class Service extends BaseEntity {
 	constructor(connection, serviceId) {
-		this.connection = connection;
+		super(connection, [["service_id", "serviceId"], "title", "description", ["process_graph", "processGraph"], "url", "type", "enabled", "parameters", "attributes", "submitted", "plan", "costs", "budget"]);
 		this.serviceId = serviceId;
 	}
 
-	_addMetadata(metadata) {
-		this.title       = metadata.title;
-		this.description = metadata.description;
-		this.url         = metadata.url;
-		this.type        = metadata.type;
-		this.enabled     = metadata.enabled;
-		this.submitted   = metadata.submitted;
-		this.plan        = metadata.plan;
-		this.costs       = metadata.costs;
-		this.budget      = metadata.budget;
-		return this;  // for chaining
-	}
-
 	describeService() {
 		return this.connection._get('/services/' + this.serviceId)
-			.then(response => response.data);
+			.then(response => this.setAll(response.data));
 	}
 
 	updateService(parameters) {
 		return this.connection._patch('/services/' + this.serviceId, parameters)
-			.then(response => response.status == 204);
+			.then(() => {
+				if (this.connection.capabilitiesObject.hasFeature('describeService')) {
+					return this.describeService();
+				}
+				else {
+					return Promise.resolve(this.setAll(parameters));
+				}
+			});
 	}
 
 	deleteService() {
-		return this.connection._delete('/services/' + this.serviceId)
-			.then(response => response.status == 204);
+		return this.connection._delete('/services/' + this.serviceId);
 	}
 }
 
diff --git a/package.json b/package.json
index 75d8a82f..18e964b6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@openeo/js-client",
-  "version": "0.3.0",
+  "version": "0.3.1",
   "author": "openEO Consortium",
   "contributors": [
     {