diff --git a/fineract-client/dependencies.gradle b/fineract-client/dependencies.gradle
index 320dfee5b..02baf8d57 100644
--- a/fineract-client/dependencies.gradle
+++ b/fineract-client/dependencies.gradle
@@ -37,7 +37,8 @@ dependencies {
 
     testImplementation(
             'org.junit.jupiter:junit-jupiter-api:5.7.0',
-            'com.google.truth:truth:1.0.1'
+            'com.google.truth:truth:1.0.1',
+            'com.google.truth.extensions:truth-java8-extension:1.0.1'
             )
     testRuntimeOnly(
             'org.junit.jupiter:junit-jupiter-engine:5.7.0'
diff --git a/fineract-client/src/main/java/org/apache/fineract/client/util/FineractClient.java b/fineract-client/src/main/java/org/apache/fineract/client/util/FineractClient.java
index 9d4dba168..a7e85395a 100644
--- a/fineract-client/src/main/java/org/apache/fineract/client/util/FineractClient.java
+++ b/fineract-client/src/main/java/org/apache/fineract/client/util/FineractClient.java
@@ -147,6 +147,15 @@ import retrofit2.converter.scalars.ScalarsConverterFactory;
  */
 public final class FineractClient {
 
+    /**
+     * Constant to be used in requests where Fineract's API requires a dateFormat to be given. This matches the format
+     * in which LocalDate instances are serialized. (BTW: In a Java client API, it seems weird to have strong LocalDate
+     * (not String) instances, and then have to specify its format, see
+     * https://issues.apache.org/jira/browse/FINERACT-1233.)
+     */
+    // Matching org.apache.fineract.client.util.JSON.LocalDateTypeAdapter.formatter
+    public static final String DATE_FORMAT = "yyyy-mm-dd";
+
     private final Retrofit retrofit;
 
     public final AccountingClosureApi glClosures;
diff --git a/fineract-client/src/main/java/org/apache/fineract/client/util/JSON.java b/fineract-client/src/main/java/org/apache/fineract/client/util/JSON.java
index 034c8b356..c1751bc63 100644
--- a/fineract-client/src/main/java/org/apache/fineract/client/util/JSON.java
+++ b/fineract-client/src/main/java/org/apache/fineract/client/util/JSON.java
@@ -97,22 +97,21 @@ class JSON {
     }
 
     /**
-     * GSON TypeAdapter for JSR-310 LocalDate type in Fineract API Format (<tt>[2009,1,1]</tt>).
+     * GSON TypeAdapter for JSR-310 LocalDate type, which Fineract API's RETURNS as JSON array in the
+     * <tt>[2009,1,1]</tt> format, but EXPECTS as String not Array and with a locale and dateFormat. Weird, but so it is
+     * (see FINERACT-1220 & FINERACT-1233).
      */
     public static class LocalDateTypeAdapter extends TypeAdapter<LocalDate> {
 
-        // Now unused: private final DateTimeFormatter formatter = DateTimeFormatter.ISO_LOCAL_DATE;
+        // NB this format is referenced from org.apache.fineract.client.util.FineractClient.DATE_FORMAT
+        private final DateTimeFormatter formatter = DateTimeFormatter.ISO_LOCAL_DATE;
 
         @Override
         public void write(JsonWriter out, LocalDate date) throws IOException {
             if (date == null) {
                 out.nullValue();
             } else {
-                out.beginArray();
-                out.value(date.getYear());
-                out.value(date.getMonthValue());
-                out.value(date.getDayOfMonth());
-                out.endArray();
+                out.value(formatter.format(date));
             }
         }
 
diff --git a/fineract-client/src/test/java/org/apache/fineract/client/testutil/CallSubject.java b/fineract-client/src/test/java/org/apache/fineract/client/testutil/CallSubject.java
new file mode 100644
index 000000000..edd4fae21
--- /dev/null
+++ b/fineract-client/src/test/java/org/apache/fineract/client/testutil/CallSubject.java
@@ -0,0 +1,55 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.client.testutil;
+
+import com.google.common.truth.FailureMetadata;
+import com.google.common.truth.Subject;
+import com.google.common.truth.Truth;
+import java.io.IOException;
+import javax.annotation.Nullable;
+import retrofit2.Call;
+
+/**
+ * Google Truth Extension for Retrofit Call.
+ *
+ * @author Michael Vorburger.ch
+ */
+public class CallSubject extends Subject {
+
+    // as per https://truth.dev/extension
+
+    public static CallSubject assertThat(@Nullable Call<?> actual) {
+        return Truth.assertAbout(calls()).that(actual);
+    }
+
+    public static Factory<CallSubject, Call<?>> calls() {
+        return CallSubject::new;
+    }
+
+    private final Call<?> actual;
+
+    protected CallSubject(FailureMetadata metadata, @Nullable Call<?> actual) {
+        super(metadata, actual);
+        this.actual = actual;
+    }
+
+    public void hasHttpStatus(int expectedHttpStatus) throws IOException {
+        check("httpStatus").that(actual.execute().code()).isEqualTo(expectedHttpStatus);
+    }
+}
diff --git a/fineract-client/src/test/java/org/apache/fineract/integrationtests/newstyle/IntegrationTest.java b/fineract-client/src/test/java/org/apache/fineract/integrationtests/newstyle/IntegrationTest.java
new file mode 100644
index 000000000..81559eed8
--- /dev/null
+++ b/fineract-client/src/test/java/org/apache/fineract/integrationtests/newstyle/IntegrationTest.java
@@ -0,0 +1,134 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.integrationtests.newstyle;
+
+import com.google.common.truth.BigDecimalSubject;
+import com.google.common.truth.BooleanSubject;
+import com.google.common.truth.ComparableSubject;
+import com.google.common.truth.DoubleSubject;
+import com.google.common.truth.FloatSubject;
+import com.google.common.truth.IntegerSubject;
+import com.google.common.truth.IterableSubject;
+import com.google.common.truth.LongSubject;
+import com.google.common.truth.OptionalSubject;
+import com.google.common.truth.StringSubject;
+import com.google.common.truth.Subject;
+import com.google.common.truth.Truth;
+import com.google.common.truth.Truth8;
+import java.math.BigDecimal;
+import java.util.Optional;
+import java.util.Random;
+import okhttp3.logging.HttpLoggingInterceptor.Level;
+import org.apache.fineract.client.testutil.CallSubject;
+import org.apache.fineract.client.util.Calls;
+import org.apache.fineract.client.util.FineractClient;
+import org.junit.jupiter.api.MethodOrderer;
+import org.junit.jupiter.api.TestMethodOrder;
+import retrofit2.Call;
+
+/**
+ * Integration Test for /documents API.
+ *
+ * @author Michael Vorburger.ch
+ */
+// TODO Remove @TestMethodOrder when https://github.com/junit-team/junit5/issues/1919 is available
+@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
+public abstract class IntegrationTest {
+
+    private static final Random random = new Random();
+
+    private FineractClient fineract;
+
+    protected FineractClient fineract() {
+        if (fineract == null) {
+            // TODO change from Fineract.dev to https://localhost:8443/fineract-provider/api/v1/ after FINERACT-1209
+            String url = System.getProperty("fineract.it.url", "https://demo.fineract.dev/fineract-provider/api/v1/");
+            fineract = FineractClient.builder().baseURL(url).tenant("default").basicAuth("mifos", "password").insecure(true)
+                    .logging(Level.BODY).build();
+        }
+        return fineract;
+    }
+
+    /**
+     * See {@link FineractClient#DATE_FORMAT}.
+     */
+    protected String dateFormat() {
+        return FineractClient.DATE_FORMAT;
+    }
+
+    protected String random() {
+        return Long.toString(random.nextLong());
+    }
+
+    // This method just makes it easier to use Calls.ok() in tests (it avoids having to static import)
+    protected <T> T ok(Call<T> call) {
+        return Calls.ok(call);
+    }
+
+    // as above, avoids import static CallSubject.assertThat
+    protected <T> CallSubject assertThat(Call<T> call) {
+        return CallSubject.assertThat(call);
+    }
+
+    // as above, this avoids issues with e.g. the Eclipse compiler getting confused which assertThat is which
+    public static IterableSubject assertThat(Iterable<?> actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static <T extends Comparable<?>> ComparableSubject<T> assertThat(T actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static BigDecimalSubject assertThat(BigDecimal actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static Subject assertThat(Object actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static LongSubject assertThat(Long actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static DoubleSubject assertThat(Double actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static FloatSubject assertThat(Float actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static IntegerSubject assertThat(Integer actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static BooleanSubject assertThat(Boolean actual) {
+        return Truth.assertThat(actual);
+    }
+
+    public static StringSubject assertThat(String actual) {
+        return Truth.assertThat(actual);
+    }
+
+    // from truth-java8-extension
+    public static OptionalSubject assertThat(Optional<?> actual) {
+        return Truth8.assertThat(actual);
+    }
+}
diff --git a/fineract-client/src/test/java/org/apache/fineract/integrationtests/newstyle/OfficeTest.java b/fineract-client/src/test/java/org/apache/fineract/integrationtests/newstyle/OfficeTest.java
new file mode 100644
index 000000000..ddfe5db0e
--- /dev/null
+++ b/fineract-client/src/test/java/org/apache/fineract/integrationtests/newstyle/OfficeTest.java
@@ -0,0 +1,48 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.integrationtests.newstyle;
+
+import java.time.LocalDate;
+import org.apache.fineract.client.models.PostOfficesRequest;
+import org.junit.jupiter.api.Order;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Integration Test for /offices API.
+ *
+ * @author Michael Vorburger.ch
+ */
+public class OfficeTest extends IntegrationTest {
+
+    @Test
+    @Order(1)
+    void createOne() {
+        // NB parentId(1) always exists (Head Office)
+        // NB name random() because Office Names have to be unique
+        // TODO requiring dateFormat(..).locale(..) is dumb :( see https://issues.apache.org/jira/browse/FINERACT-1233
+        assertThat(ok(fineract().offices.createOffice(new PostOfficesRequest().name("TestOffice-" + random()).parentId(1L)
+                .openingDate(LocalDate.now()).dateFormat(dateFormat()).locale("en_US"))).getOfficeId()).isGreaterThan(0);
+    }
+
+    @Test
+    @Order(2)
+    void retrieveOneExisting() {
+        assertThat(ok(fineract().offices.retrieveOffices(true, null, null)).size()).isAtLeast(2);
+    }
+}