diff --git a/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/oa/graph/dump/APIClient.java b/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/oa/graph/dump/APIClient.java
index 02c812723..23322f7fe 100644
--- a/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/oa/graph/dump/APIClient.java
+++ b/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/oa/graph/dump/APIClient.java
@@ -3,28 +3,10 @@ package eu.dnetlib.dhp.oa.graph.dump;
 
 import java.io.*;
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
-
-import org.apache.commons.io.FileUtils;
-import org.apache.http.HttpEntity;
-import org.apache.http.HttpResponse;
-import org.apache.http.client.HttpClient;
-import org.apache.http.client.methods.HttpPost;
-import org.apache.http.client.methods.HttpPut;
-import org.apache.http.entity.ByteArrayEntity;
-import org.apache.http.entity.InputStreamEntity;
-import org.apache.http.entity.StringEntity;
-//import org.apache.http.entity.mime.MultipartEntityBuilder;
-import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.DefaultHttpClient;
-import org.apache.http.impl.client.HttpClients;
-import org.apache.http.util.EntityUtils;
-
+import okhttp3.*;
 import com.google.gson.Gson;
-
 import eu.dnetlib.dhp.oa.graph.dump.zenodo.ZenodoModel;
 
-//import org.apache.http.entity.mime.MultipartEntityBuilder;
 
 public class APIClient implements Serializable {
 
@@ -34,6 +16,12 @@ public class APIClient implements Serializable {
 	String deposition_id;
 	String access_token;
 
+	public static final MediaType MEDIA_TYPE_JSON
+			= MediaType.parse("application/json; charset=utf-8");
+
+	private static final MediaType MEDIA_TYPE_ZIP
+			= MediaType.parse("application/zip");
+
 	public String getUrlString() {
 		return urlString;
 	}
@@ -56,31 +44,134 @@ public class APIClient implements Serializable {
 		this.access_token = access_token;
 	}
 
-	public int connect() throws IOException {
+	public int connect() throws IOException{
+		String json = "{}";
+		OkHttpClient httpClient = new OkHttpClient();
+
+		RequestBody body = RequestBody.create(json, MEDIA_TYPE_JSON);
+
+		Request request = new Request.Builder()
+				.url(urlString)
+				.addHeader("Content-Type", "application/json")  // add request headers
+				.addHeader("Authorization", "Bearer " + access_token)
+				.post(body)
+				.build();
+
+
+
+		try (Response response = httpClient.newCall(request).execute()) {
+
+			if (!response.isSuccessful()) throw new IOException("Unexpected code " + response + response.body().string());
+
+			// Get response body
+			json = response.body().string();
+
+			ZenodoModel newSubmission = new Gson().fromJson(json, ZenodoModel.class);
+			this.bucket = newSubmission.getLinks().getBucket();
+			this.deposition_id = newSubmission.getId();
+
+			return response.code();
+
+		}
+
+	}
+
+
+	public int upload(File file, String file_name){
+
+		OkHttpClient httpClient = new OkHttpClient();
+
+		Request request = new Request.Builder()
+				.url(bucket + "/" + file_name)
+				.addHeader("Content-Type", "application/zip")  // add request headers
+				.addHeader("Authorization", "Bearer " + access_token)
+				.put(RequestBody.create(file, MEDIA_TYPE_ZIP))
+				.build();
+
+		try (Response response = httpClient.newCall(request).execute()) {
+			if (!response.isSuccessful()) throw new IOException("Unexpected code " + response + response.body().string());
+			return response.code();
+		} catch (IOException e) {
+			e.printStackTrace();
+
+		}
+
+		return -1;
+	}
+
+
+	public int sendMretadata(String metadata) throws IOException {
+
+		OkHttpClient httpClient = new OkHttpClient();
+
+		RequestBody body = RequestBody.create(metadata, MEDIA_TYPE_JSON);
+
+		Request request = new Request.Builder()
+				.url(urlString + "/" + deposition_id)
+				.addHeader("Content-Type", "application/json")  // add request headers
+				.addHeader("Authorization", "Bearer " + access_token)
+				.put(body)
+				.build();
+
+
+		try (Response response = httpClient.newCall(request).execute()) {
+
+			if (!response.isSuccessful()) throw new IOException("Unexpected code " + response + response.body().string());
+
+			return response.code();
+
+		}
+
+	}
+
+	public int publish() throws IOException {
 
 		String json = "{}";
 
-		HttpClient client = new DefaultHttpClient();
+		OkHttpClient httpClient = new OkHttpClient();
 
-		HttpPost post = new HttpPost(urlString);
 
-		StringEntity input = new StringEntity(json);
-		post.setEntity(input);
-		post.addHeader("Content-Type", "application/json");
-		post.setHeader("Authorization", "Bearer " + access_token);
+		Request request = new Request.Builder()
+				.url(urlString + "/" + deposition_id + "/actions/publish")
+				.addHeader("Authorization", "Bearer " + access_token)
+				.post(RequestBody.create(json, MEDIA_TYPE_JSON))
+				.build();
 
-		HttpResponse response = client.execute(post);
+		try (Response response = httpClient.newCall(request).execute()) {
 
-		json = EntityUtils.toString(response.getEntity());
+			if (!response.isSuccessful()) throw new IOException("Unexpected code " + response + response.body().string());
 
-		ZenodoModel newSubmission = new Gson().fromJson(json, ZenodoModel.class);
-		this.bucket = newSubmission.getLinks().getBucket();
-		this.deposition_id = newSubmission.getId();
-
-		return response.getStatusLine().getStatusCode();
+			return response.code();
 
+		}
 	}
 
+	//	public int connect() throws IOException {
+//
+//		String json = "{}";
+//
+//		HttpClient client = new DefaultHttpClient();
+//
+//		HttpPost post = new HttpPost(urlString);
+//
+//		StringEntity input = new StringEntity(json);
+//		post.setEntity(input);
+//		post.addHeader("Content-Type", "application/json");
+//		post.setHeader("Authorization", "Bearer " + access_token);
+//
+//
+//		HttpResponse response = client.execute(post);
+//
+//		json = EntityUtils.toString(response.getEntity());
+//
+//		ZenodoModel newSubmission = new Gson().fromJson(json, ZenodoModel.class);
+//		this.bucket = newSubmission.getLinks().getBucket();
+//		this.deposition_id = newSubmission.getId();
+//
+//		return response.getStatusLine().getStatusCode();
+//
+//	}
+
 //	public int upload(InputStream is, String file_name) throws IOException {
 //		HttpClient client = new DefaultHttpClient();
 //
@@ -100,52 +191,52 @@ public class APIClient implements Serializable {
 //		return response.getStatusLine().getStatusCode();
 //	}
 
-	public int upload(File file, String file_name) throws IOException {
-		HttpClient client = new DefaultHttpClient();
+//	public int upload(File file, String file_name) throws IOException {
+//		HttpClient client = new DefaultHttpClient();
+//
+//		HttpPut put = new HttpPut(bucket + "/" + file_name);
+//		put.setHeader("Authorization", "Bearer " + access_token);
+//		put.addHeader("Content-Type", "application/zip");
+//		InputStreamEntity data = new InputStreamEntity(new FileInputStream(file), -1);
+//		data.setContentType("binary/octet-stream");
+//		data.setChunked(true); // Send in multiple parts if needed
+////		ByteArrayInputStream bais = new ByteArrayInputStream(FileUtils.readFileToByteArray(file));
+////		EntityUtils.toByteArray(new ByteArrayInputStream(FileUtils.readFileToByteArray(file)));
+////		InputStream targetStream = new FileInputStream(file);
+////		DataInputStream tmp = new DataInputStream(targetStream);
+////		HttpEntity data = new ByteArrayEntity(tmp.);
+////		HttpEntity data = MultipartEntityBuilder.create().addBinaryBody(file_name, file).build();
+//		put.setEntity(data);
+//
+//		HttpResponse response = client.execute(put);
+//
+//		return response.getStatusLine().getStatusCode();
+//
+//	}
 
-		HttpPut put = new HttpPut(bucket + "/" + file_name);
-		put.setHeader("Authorization", "Bearer " + access_token);
-		put.addHeader("Content-Type", "application/zip");
-		InputStreamEntity data = new InputStreamEntity(new FileInputStream(file), -1);
-		data.setContentType("binary/octet-stream");
-		data.setChunked(true); // Send in multiple parts if needed
-//		ByteArrayInputStream bais = new ByteArrayInputStream(FileUtils.readFileToByteArray(file));
-//		EntityUtils.toByteArray(new ByteArrayInputStream(FileUtils.readFileToByteArray(file)));
-//		InputStream targetStream = new FileInputStream(file);
-//		DataInputStream tmp = new DataInputStream(targetStream);
-//		HttpEntity data = new ByteArrayEntity(tmp.);
-//		HttpEntity data = MultipartEntityBuilder.create().addBinaryBody(file_name, file).build();
-		put.setEntity(data);
+//	public int sendMretadata(String metadata) throws IOException {
+//
+//		HttpClient client = new DefaultHttpClient();
+//		HttpPut post = new HttpPut(urlString + "/" + deposition_id);
+//		post.setHeader("Authorization", "Bearer " + access_token);
+//		post.addHeader("Content-Type", "application/json");
+//		StringEntity entity = new StringEntity(metadata, StandardCharsets.UTF_8);
+//		post.setEntity(entity);
+//
+//		HttpResponse response = client.execute(post);
+//
+//		return response.getStatusLine().getStatusCode();
+//
+//	}
 
-		HttpResponse response = client.execute(put);
-
-		return response.getStatusLine().getStatusCode();
-
-	}
-
-	public int sendMretadata(String metadata) throws IOException {
-
-		HttpClient client = new DefaultHttpClient();
-		HttpPut post = new HttpPut(urlString + "/" + deposition_id);
-		post.setHeader("Authorization", "Bearer " + access_token);
-		post.addHeader("Content-Type", "application/json");
-		StringEntity entity = new StringEntity(metadata, StandardCharsets.UTF_8);
-		post.setEntity(entity);
-
-		HttpResponse response = client.execute(post);
-
-		return response.getStatusLine().getStatusCode();
-
-	}
-
-	public int publish() throws IOException {
-		HttpClient client = new DefaultHttpClient();
-		HttpPost post = new HttpPost(urlString + "/" + deposition_id + "/actions/publish");
-		post.setHeader("Authorization", "Bearer " + access_token);
-
-		HttpResponse response = client.execute(post);
-
-		return response.getStatusLine().getStatusCode();
-	}
+//	public int publish() throws IOException {
+//		HttpClient client = new DefaultHttpClient();
+//		HttpPost post = new HttpPost(urlString + "/" + deposition_id + "/actions/publish");
+//		post.setHeader("Authorization", "Bearer " + access_token);
+//
+//		HttpResponse response = client.execute(post);
+//
+//		return response.getStatusLine().getStatusCode();
+//	}
 
 }