diff --git a/pom.xml b/pom.xml
index c2d3ea0..da9bb34 100644
--- a/pom.xml
+++ b/pom.xml
@@ -122,19 +122,19 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.5.1</version>
+            <version>5.5.2</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-migrationsupport</artifactId>
-            <version>5.5.1</version>
+            <version>5.5.2</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.hamcrest</groupId>
-            <artifactId>hamcrest-junit</artifactId>
-            <version>2.0.0.0</version>
+            <artifactId>hamcrest</artifactId>
+            <version>2.1</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -146,13 +146,36 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>3.0.0</version>
+            <version>3.1.0</version>
             <scope>test</scope>
+            <exclusions>
+                <exclusion>
+                    <groupId>net.bytebuddy</groupId>
+                    <artifactId>byte-buddy</artifactId>
+                </exclusion>
+                <exclusion>
+                    <groupId>net.bytebuddy</groupId>
+                    <artifactId>byte-buddy-agent</artifactId>
+                </exclusion>
+            </exclusions>
         </dependency>
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-inline</artifactId>
-            <version>3.0.0</version>
+            <version>3.1.0</version>
+            <scope>test</scope>
+        </dependency>
+        <!-- Updated transient dependency from mockito-core for JDK 13 compatibility -->
+        <dependency>
+            <groupId>net.bytebuddy</groupId>
+            <artifactId>byte-buddy</artifactId>
+            <version>1.9.16</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>net.bytebuddy</groupId>
+            <artifactId>byte-buddy-agent</artifactId>
+            <version>1.9.16</version>
             <scope>test</scope>
         </dependency>
         <dependency>
diff --git a/src/test/java/de/stklcode/jvault/connector/HTTPVaultConnectorTest.java b/src/test/java/de/stklcode/jvault/connector/HTTPVaultConnectorTest.java
index 58ac6e3..3fc4461 100644
--- a/src/test/java/de/stklcode/jvault/connector/HTTPVaultConnectorTest.java
+++ b/src/test/java/de/stklcode/jvault/connector/HTTPVaultConnectorTest.java
@@ -39,11 +39,9 @@ import static org.apache.commons.io.FileUtils.copyDirectory;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.hamcrest.core.Is.is;
-import static org.hamcrest.junit.MatcherAssume.assumeThat;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.fail;
-import static org.junit.jupiter.api.Assumptions.assumeFalse;
-import static org.junit.jupiter.api.Assumptions.assumeTrue;
+import static org.junit.jupiter.api.Assumptions.*;
 
 /**
  * JUnit test for HTTP Vault connector.
@@ -292,7 +290,7 @@ public class HTTPVaultConnectorTest {
             } catch (VaultConnectorException e) {
                 fail("Written secret could not be read.");
             }
-            assumeThat(res, is(notNullValue()));
+            assumeTrue(res != null);
 
             /* Delete secret */
             try {
@@ -333,7 +331,7 @@ public class HTTPVaultConnectorTest {
             } catch (VaultConnectorException e) {
                 fail("Written secret could not be read.");
             }
-            assumeThat(res, is(notNullValue()));
+            assumeTrue(res != null);
 
             /* Revoke secret */
             try {
@@ -460,7 +458,7 @@ public class HTTPVaultConnectorTest {
             try {
                 MetadataResponse res = connector.readSecretMetadata(MOUNT_KV2, SECRET2_KEY);
                 maxVersions = res.getMetadata().getMaxVersions();
-                assumeThat("Unexpected maximum number of versions", res.getMetadata().getMaxVersions(), is(10));
+                assumeTrue(res.getMetadata().getMaxVersions() == 10, "Unexpected maximum number of versions");
             } catch (VaultConnectorException e) {
                 fail("Reading secret metadata failed: " + e.getMessage());
             }
diff --git a/src/test/java/de/stklcode/jvault/connector/model/AppRoleSecretTest.java b/src/test/java/de/stklcode/jvault/connector/model/AppRoleSecretTest.java
index deaacf6..fbabb32 100644
--- a/src/test/java/de/stklcode/jvault/connector/model/AppRoleSecretTest.java
+++ b/src/test/java/de/stklcode/jvault/connector/model/AppRoleSecretTest.java
@@ -29,8 +29,8 @@ import java.util.Map;
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
-import static org.hamcrest.junit.MatcherAssume.assumeThat;
 import static org.junit.jupiter.api.Assertions.fail;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
 
 /**
@@ -143,17 +143,17 @@ public class AppRoleSecretTest {
 
         /* Test fields, that should not be written to JSON */
         setPrivateField(secret, "accessor", "TEST_ACCESSOR");
-        assumeThat(secret.getAccessor(), is("TEST_ACCESSOR"));
+        assumeTrue("TEST_ACCESSOR".equals(secret.getAccessor()));
         setPrivateField(secret, "creationTime", "TEST_CREATION");
-        assumeThat(secret.getCreationTime(), is("TEST_CREATION"));
+        assumeTrue("TEST_CREATION".equals(secret.getCreationTime()));
         setPrivateField(secret, "expirationTime", "TEST_EXPIRATION");
-        assumeThat(secret.getExpirationTime(), is("TEST_EXPIRATION"));
+        assumeTrue("TEST_EXPIRATION".equals(secret.getExpirationTime()));
         setPrivateField(secret, "lastUpdatedTime", "TEST_UPDATETIME");
-        assumeThat(secret.getLastUpdatedTime(), is("TEST_UPDATETIME"));
+        assumeTrue("TEST_UPDATETIME".equals(secret.getLastUpdatedTime()));
         setPrivateField(secret, "numUses", 678);
-        assumeThat(secret.getNumUses(), is(678));
+        assumeTrue(secret.getNumUses() == 678);
         setPrivateField(secret, "ttl", 12345);
-        assumeThat(secret.getTtl(), is(12345));
+        assumeTrue(secret.getTtl() == 12345);
         try {
             secretJson = mapper.writeValueAsString(secret);
         } catch (JsonProcessingException e) {