diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ee030c12..8aaa3be7 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -8,7 +8,7 @@ jobs:
 
     strategy:
       matrix:
-        java-version: [8, 11, 17]
+        java-version: [8, 11, 17, 21]
     
     steps:
       - uses: actions/checkout@v3
diff --git a/pom.xml b/pom.xml
index 0e84e8c2..b8938544 100644
--- a/pom.xml
+++ b/pom.xml
@@ -272,6 +272,12 @@
             <version>4.11.0</version>
             <scope>test</scope>
         </dependency>
+        <!-- Support Mockito 4.x for Java 21 -->
+        <dependency>
+            <groupId>net.bytebuddy</groupId>
+            <artifactId>byte-buddy</artifactId>
+            <version>1.14.11</version>
+        </dependency>
         <dependency>
             <groupId>commons-io</groupId>
             <artifactId>commons-io</artifactId>
diff --git a/src/test/java/com/bitpay/sdk/model/settlement/SettlementTest.java b/src/test/java/com/bitpay/sdk/model/settlement/SettlementTest.java
index 381f5efc..380d0d56 100644
--- a/src/test/java/com/bitpay/sdk/model/settlement/SettlementTest.java
+++ b/src/test/java/com/bitpay/sdk/model/settlement/SettlementTest.java
@@ -4,6 +4,7 @@
 
 package com.bitpay.sdk.model.settlement;
 
+import java.time.ZonedDateTime;
 import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Assertions;
@@ -76,84 +77,84 @@ public void it_should_change_status() {
         // then
         Assertions.assertEquals(expected, testedClass.getStatus());
     }
-//
-//    @Test
-//    public void it_should_change_dateCreated() {
-//        // given
-//        Long expected = 12L;
-//        Settlement testedClass = this.getTestedClass();
-//
-//        // when
-//        testedClass.setDateCreated(expected);
-//
-//        // then
-//        Assertions.assertEquals(expected, testedClass.getDateCreated());
-//    }
-//
-//    @Test
-//    public void it_should_change_dateExecuted() {
-//        // given
-//        Long expected = 12L;
-//        Settlement testedClass = this.getTestedClass();
-//
-//        // when
-//        testedClass.setDateExecuted(expected);
-//
-//        // then
-//        Assertions.assertEquals(expected, testedClass.getDateExecuted());
-//    }
-//
-//    @Test
-//    public void it_should_change_dateCompleted() {
-//        // given
-//        Long expected = 12L;
-//        Settlement testedClass = this.getTestedClass();
-//
-//        // when
-//        testedClass.setDateCompleted(expected);
-//
-//        // then
-//        Assertions.assertEquals(expected, testedClass.getDateCompleted());
-//    }
-//
-//    @Test
-//    public void it_should_change_openingDate() {
-//        // given
-//        Long expected = 12L;
-//        Settlement testedClass = this.getTestedClass();
-//
-//        // when
-//        testedClass.setOpeningDate(expected);
-//
-//        // then
-//        Assertions.assertEquals(expected, testedClass.getOpeningDate());
-//    }
-//
-//    @Test
-//    public void it_should_change_closingDate() {
-//        // given
-//        Long expected = 12L;
-//        Settlement testedClass = this.getTestedClass();
-//
-//        // when
-//        testedClass.setClosingDate(expected);
-//
-//        // then
-//        Assertions.assertEquals(expected, testedClass.getClosingDate());
-//    }
-//
-//    @Test
-//    public void it_should_change_openingBalance() {
-//        // given
-//        Float expected = 12.34F;
-//        Settlement testedClass = this.getTestedClass();
-//
-//        // when
-//        testedClass.setOpeningBalance(expected);
-//
-//        // then
-//        Assertions.assertEquals(expected, testedClass.getOpeningBalance());
-//    }
+
+    @Test
+    public void it_should_change_dateCreated() {
+        // given
+        ZonedDateTime expected = ZonedDateTime.now();
+        Settlement testedClass = this.getTestedClass();
+
+        // when
+        testedClass.setDateCreated(expected);
+
+        // then
+        Assertions.assertEquals(expected, testedClass.getDateCreated());
+    }
+
+    @Test
+    public void it_should_change_dateExecuted() {
+        // given
+        ZonedDateTime expected = ZonedDateTime.now();
+        Settlement testedClass = this.getTestedClass();
+
+        // when
+        testedClass.setDateExecuted(expected);
+
+        // then
+        Assertions.assertEquals(expected, testedClass.getDateExecuted());
+    }
+
+    @Test
+    public void it_should_change_dateCompleted() {
+        // given
+        ZonedDateTime expected = ZonedDateTime.now();
+        Settlement testedClass = this.getTestedClass();
+
+        // when
+        testedClass.setDateCompleted(expected);
+
+        // then
+        Assertions.assertEquals(expected, testedClass.getDateCompleted());
+    }
+
+    @Test
+    public void it_should_change_openingDate() {
+        // given
+        ZonedDateTime expected = ZonedDateTime.now();
+        Settlement testedClass = this.getTestedClass();
+
+        // when
+        testedClass.setOpeningDate(expected);
+
+        // then
+        Assertions.assertEquals(expected, testedClass.getOpeningDate());
+    }
+
+    @Test
+    public void it_should_change_closingDate() {
+        // given
+        ZonedDateTime expected = ZonedDateTime.now();
+        Settlement testedClass = this.getTestedClass();
+
+        // when
+        testedClass.setClosingDate(expected);
+
+        // then
+        Assertions.assertEquals(expected, testedClass.getClosingDate());
+    }
+
+    @Test
+    public void it_should_change_openingBalance() {
+        // given
+        Float expected = 12.34F;
+        Settlement testedClass = this.getTestedClass();
+
+        // when
+        testedClass.setOpeningBalance(expected);
+
+        // then
+        Assertions.assertEquals(expected, testedClass.getOpeningBalance());
+    }
 
     @Test
     public void it_should_change_ledgerEntriesSum() {