diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 317a44113..1163518d0 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -32,12 +32,10 @@ jobs:
       fail-fast: false
       matrix:
         docker-img:
-          - docker.io/arangodb/arangodb:3.6.13
-          - docker.io/arangodb/arangodb:3.7.12
-          - arangodb/arangodb-preview:3.8.0-rc.2
-          - docker.io/arangodb/enterprise:3.6.13
-          - docker.io/arangodb/enterprise:3.7.12
-          - arangodb/enterprise-preview:3.8.0-rc.2
+          - docker.io/arangodb/arangodb:3.7.15
+          - docker.io/arangodb/arangodb:3.8.1
+          - docker.io/arangodb/enterprise:3.7.15
+          - docker.io/arangodb/enterprise:3.8.1
 
         topology:
           - single
@@ -59,3 +57,37 @@ jobs:
       - name: Debug containers
         if: ${{ cancelled() || failure() }}
         run: ./docker/debug_containers_${{ matrix.topology }}.sh
+
+  test-locale:
+    timeout-minutes: 20
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        docker-img:
+#          - docker.io/arangodb/arangodb:3.7.15
+          - docker.io/arangodb/arangodb:3.8.1
+#          - docker.io/arangodb/enterprise:3.7.15
+#          - docker.io/arangodb/enterprise:3.8.1
+
+        topology:
+          - single
+#          - cluster
+#          - active-failover
+
+    steps:
+      - uses: actions/checkout@v1
+      - name: Set up JDK 1.8
+        uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+      - name: Start Database
+        run: ./docker/start_db_${{ matrix.topology }}_retry_fail.sh ${{ matrix.docker-img }}
+        env:
+          ARANGO_LICENSE_KEY: ${{ secrets.ARANGO_LICENSE_KEY }}
+      - name: Test
+        run: mvn --no-transfer-progress test -DargLine="-Duser.language=tr"
+      - name: Debug containers
+        if: ${{ cancelled() || failure() }}
+        run: ./docker/debug_containers_${{ matrix.topology }}.sh
diff --git a/src/main/java/com/arangodb/ArangoDB.java b/src/main/java/com/arangodb/ArangoDB.java
index d0f08b3ae..25a0738f8 100644
--- a/src/main/java/com/arangodb/ArangoDB.java
+++ b/src/main/java/com/arangodb/ArangoDB.java
@@ -75,6 +75,7 @@
 import java.io.InputStream;
 import java.lang.annotation.Annotation;
 import java.util.Collection;
+import java.util.Locale;
 import java.util.Properties;
 
 /**
@@ -119,7 +120,7 @@ protected void loadProperties(final Properties properties) {
         private static Protocol loadProtocol(final Properties properties, final Protocol currentValue) {
             return Protocol.valueOf(
                     getProperty(properties, PROPERTY_KEY_PROTOCOL, currentValue, ArangoDefaults.DEFAULT_NETWORK_PROTOCOL)
-                            .toUpperCase());
+                            .toUpperCase(Locale.ENGLISH));
         }
 
         public Builder useProtocol(final Protocol protocol) {
diff --git a/src/main/java/com/arangodb/internal/InternalArangoDBBuilder.java b/src/main/java/com/arangodb/internal/InternalArangoDBBuilder.java
index 8a06f6564..3b238a751 100644
--- a/src/main/java/com/arangodb/internal/InternalArangoDBBuilder.java
+++ b/src/main/java/com/arangodb/internal/InternalArangoDBBuilder.java
@@ -50,10 +50,7 @@
 import javax.net.ssl.SSLContext;
 import java.io.IOException;
 import java.io.InputStream;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
-import java.util.Properties;
+import java.util.*;
 
 
 /**
@@ -353,7 +350,7 @@ private static LoadBalancingStrategy loadLoadBalancingStrategy(
             final Properties properties,
             final LoadBalancingStrategy currentValue) {
         return LoadBalancingStrategy.valueOf(getProperty(properties, PROPERTY_KEY_LOAD_BALANCING_STRATEGY, currentValue,
-                ArangoDefaults.DEFAULT_LOAD_BALANCING_STRATEGY).toUpperCase());
+                ArangoDefaults.DEFAULT_LOAD_BALANCING_STRATEGY).toUpperCase(Locale.ENGLISH));
     }
 
     protected static <T> String getProperty(
diff --git a/src/main/java/com/arangodb/internal/velocypack/VPackDeserializers.java b/src/main/java/com/arangodb/internal/velocypack/VPackDeserializers.java
index 56cfe2eab..8308c4b7a 100644
--- a/src/main/java/com/arangodb/internal/velocypack/VPackDeserializers.java
+++ b/src/main/java/com/arangodb/internal/velocypack/VPackDeserializers.java
@@ -65,11 +65,7 @@
 
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
-import java.util.ArrayList;
-import java.util.Date;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.Map.Entry;
 
 /**
@@ -144,11 +140,11 @@ public class VPackDeserializers {
 
     public static final VPackDeserializer<LogLevel> LOG_LEVEL = (parent, vpack, context) -> LogLevel.fromLevel(vpack.getAsInt());
 
-    public static final VPackDeserializer<License> LICENSE = (parent, vpack, context) -> License.valueOf(vpack.getAsString().toUpperCase());
+    public static final VPackDeserializer<License> LICENSE = (parent, vpack, context) -> License.valueOf(vpack.getAsString().toUpperCase(Locale.ENGLISH));
 
-    public static final VPackDeserializer<Permissions> PERMISSIONS = (parent, vpack, context) -> Permissions.valueOf(vpack.getAsString().toUpperCase());
+    public static final VPackDeserializer<Permissions> PERMISSIONS = (parent, vpack, context) -> Permissions.valueOf(vpack.getAsString().toUpperCase(Locale.ENGLISH));
 
-    public static final VPackDeserializer<QueryExecutionState> QUERY_EXECUTION_STATE = (parent, vpack, context) -> QueryExecutionState.valueOf(vpack.getAsString().toUpperCase().replaceAll(" ", "_"));
+    public static final VPackDeserializer<QueryExecutionState> QUERY_EXECUTION_STATE = (parent, vpack, context) -> QueryExecutionState.valueOf(vpack.getAsString().toUpperCase(Locale.ENGLISH).replaceAll(" ", "_"));
 
     public static final VPackDeserializer<ReplicationFactor> REPLICATION_FACTOR = (parent, vpack, context) -> {
         final ReplicationFactor replicationFactor = new ReplicationFactor();
@@ -167,7 +163,7 @@ public class VPackDeserializers {
     };
 
     public static final VPackDeserializer<ViewType> VIEW_TYPE = (parent, vpack, context) -> "arangosearch".equals(vpack.getAsString()) ? ViewType.ARANGO_SEARCH
-            : ViewType.valueOf(vpack.getAsString().toUpperCase());
+            : ViewType.valueOf(vpack.getAsString().toUpperCase(Locale.ENGLISH));
 
     public static final VPackDeserializer<ArangoSearchProperties> ARANGO_SEARCH_PROPERTIES = (parent, vpack, context) -> {
         final ArangoSearchProperties properties = new ArangoSearchProperties();
@@ -216,7 +212,7 @@ public class VPackDeserializers {
                 }
                 final VPackSlice storeValues = value.get("storeValues");
                 if (storeValues.isString()) {
-                    link.storeValues(StoreValuesType.valueOf(storeValues.getAsString().toUpperCase()));
+                    link.storeValues(StoreValuesType.valueOf(storeValues.getAsString().toUpperCase(Locale.ENGLISH)));
                 }
                 final VPackSlice fields = value.get("fields");
                 if (fields.isObject()) {
@@ -290,7 +286,7 @@ protected static FieldLink deserializeField(final Entry<String, VPackSlice> fiel
         }
         final VPackSlice storeValues = value.get("storeValues");
         if (storeValues.isString()) {
-            link.storeValues(StoreValuesType.valueOf(storeValues.getAsString().toUpperCase()));
+            link.storeValues(StoreValuesType.valueOf(storeValues.getAsString().toUpperCase(Locale.ENGLISH)));
         }
         final VPackSlice fields = value.get("fields");
         if (fields.isObject()) {
@@ -313,7 +309,7 @@ protected static FieldLink deserializeField(final Entry<String, VPackSlice> fiel
         final VPackSlice type = vpack.get("type");
         if (type.isString()) {
             final ConsolidationPolicy consolidate = ConsolidationPolicy
-                    .of(ConsolidationType.valueOf(type.getAsString().toUpperCase()));
+                    .of(ConsolidationType.valueOf(type.getAsString().toUpperCase(Locale.ENGLISH)));
             final VPackSlice threshold = vpack.get("threshold");
             if (threshold.isNumber()) {
                 consolidate.threshold(threshold.getAsDouble());
diff --git a/src/main/java/com/arangodb/internal/velocypack/VPackSerializers.java b/src/main/java/com/arangodb/internal/velocypack/VPackSerializers.java
index 6bacf6b92..9c7884e2f 100644
--- a/src/main/java/com/arangodb/internal/velocypack/VPackSerializers.java
+++ b/src/main/java/com/arangodb/internal/velocypack/VPackSerializers.java
@@ -51,6 +51,7 @@
 
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Map.Entry;
 
@@ -119,7 +120,7 @@ public class VPackSerializers {
 
     public static final VPackSerializer<LogLevel> LOG_LEVEL = (builder, attribute, value, context) -> builder.add(attribute, value.getLevel());
 
-    public static final VPackSerializer<Permissions> PERMISSIONS = (builder, attribute, value, context) -> builder.add(attribute, value.toString().toLowerCase());
+    public static final VPackSerializer<Permissions> PERMISSIONS = (builder, attribute, value, context) -> builder.add(attribute, value.toString().toLowerCase(Locale.ENGLISH));
 
     public static final VPackSerializer<ReplicationFactor> REPLICATION_FACTOR = (builder, attribute, value, context) -> {
         final Boolean satellite = value.getSatellite();
@@ -137,7 +138,7 @@ public class VPackSerializers {
     };
 
     public static final VPackSerializer<ViewType> VIEW_TYPE = (builder, attribute, value, context) -> {
-        final String type = value == ViewType.ARANGO_SEARCH ? "arangosearch" : value.name().toLowerCase();
+        final String type = value == ViewType.ARANGO_SEARCH ? "arangosearch" : value.name().toLowerCase(Locale.ENGLISH);
         builder.add(attribute, type);
     };
 
@@ -187,7 +188,7 @@ public class VPackSerializers {
                 }
                 final StoreValuesType storeValues = collectionLink.getStoreValues();
                 if (storeValues != null) {
-                    builder.add("storeValues", storeValues.name().toLowerCase());
+                    builder.add("storeValues", storeValues.name().toLowerCase(Locale.ENGLISH));
                 }
                 serializeFieldLinks(builder, collectionLink.getFields());
                 builder.close();
@@ -253,7 +254,7 @@ private static void serializeFieldLinks(final VPackBuilder builder, final Collec
                 }
                 final StoreValuesType storeValues = fieldLink.getStoreValues();
                 if (storeValues != null) {
-                    builder.add("storeValues", storeValues.name().toLowerCase());
+                    builder.add("storeValues", storeValues.name().toLowerCase(Locale.ENGLISH));
                 }
                 serializeFieldLinks(builder, fieldLink.getFields());
                 builder.close();
@@ -262,7 +263,7 @@ private static void serializeFieldLinks(final VPackBuilder builder, final Collec
         }
     }
 
-    public static final VPackSerializer<ConsolidationType> CONSOLIDATE_TYPE = (builder, attribute, value, context) -> builder.add(attribute, value.toString().toLowerCase());
+    public static final VPackSerializer<ConsolidationType> CONSOLIDATE_TYPE = (builder, attribute, value, context) -> builder.add(attribute, value.toString().toLowerCase(Locale.ENGLISH));
 
     public static final VPackSerializer<CollectionSchema> COLLECTION_VALIDATION = (builder, attribute, value, context) -> {
         VPackParser parser = new VPackParser.Builder().build();