diff --git a/pom.xml b/pom.xml
index d7924adb9d..4147bdcb86 100644
--- a/pom.xml
+++ b/pom.xml
@@ -17,7 +17,7 @@
     <dependency>
       <groupId>com.squareup.okhttp3</groupId>
       <artifactId>okhttp</artifactId>
-      <version>3.12.13</version>
+      <version>4.12.0</version>
     </dependency>
     <dependency>
       <groupId>com.google.code.gson</groupId>
@@ -27,13 +27,18 @@
     <dependency>
       <groupId>com.squareup.okhttp3</groupId>
       <artifactId>logging-interceptor</artifactId>
-      <version>3.12.13</version>
+      <version>4.12.0</version>
     </dependency>
     <dependency>
       <groupId>org.apache.commons</groupId>
       <artifactId>commons-configuration2</artifactId>
       <version>2.12.0</version>
     </dependency>
+    <dependency>
+      <groupId>javax.xml.bind</groupId>
+      <artifactId>jaxb-api</artifactId>
+      <version>2.3.0</version>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
@@ -63,8 +68,8 @@
         <artifactId>maven-compiler-plugin</artifactId>
         <version>2.3.2</version>
         <configuration>
-          <source>1.7</source>
-          <target>1.7</target>
+          <source>1.8</source>
+          <target>1.8</target>
           <encoding>UTF-8</encoding>
         </configuration>
       </plugin>
diff --git a/src/main/java/com/tencentcloudapi/common/AbstractClient.java b/src/main/java/com/tencentcloudapi/common/AbstractClient.java
index 6efabaceb0..6531e70ee9 100644
--- a/src/main/java/com/tencentcloudapi/common/AbstractClient.java
+++ b/src/main/java/com/tencentcloudapi/common/AbstractClient.java
@@ -32,6 +32,8 @@
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLSocketFactory;
+import javax.net.ssl.TrustManager;
+import javax.net.ssl.TrustManagerFactory;
 import javax.net.ssl.X509TrustManager;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -43,6 +45,7 @@
 import java.net.Proxy;
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
+import java.security.KeyStore;
 import java.security.SecureRandom;
 import java.sql.Date;
 import java.text.SimpleDateFormat;
@@ -420,11 +423,25 @@ private void trySetSSLSocketFactory(HttpConnection conn) {
         SSLSocketFactory sslSocketFactory = this.profile.getHttpProfile().getSslSocketFactory();
         X509TrustManager trustManager = this.profile.getHttpProfile().getX509TrustManager();
         if (sslSocketFactory != null) {
-            if (trustManager != null) {
-                this.httpConnection.setSSLSocketFactory(sslSocketFactory, trustManager);
-            } else {
-                this.httpConnection.setSSLSocketFactory(sslSocketFactory);
+            if (trustManager == null) {
+                // okhttp 4.x requires an explicit X509TrustManager alongside SSLSocketFactory.
+                // Fall back to the JVM default TrustManager so existing callers that only set
+                // SSLSocketFactory continue to work without requiring API changes.
+                try {
+                    TrustManagerFactory tmf = TrustManagerFactory.getInstance(
+                            TrustManagerFactory.getDefaultAlgorithm());
+                    tmf.init((KeyStore) null);
+                    for (TrustManager tm : tmf.getTrustManagers()) {
+                        if (tm instanceof X509TrustManager) {
+                            trustManager = (X509TrustManager) tm;
+                            break;
+                        }
+                    }
+                } catch (Exception e) {
+                    throw new RuntimeException("Failed to obtain default X509TrustManager for okhttp", e);
+                }
             }
+            this.httpConnection.setSSLSocketFactory(sslSocketFactory, trustManager);
         }
     }
 
diff --git a/src/main/java/com/tencentcloudapi/common/http/HttpConnection.java b/src/main/java/com/tencentcloudapi/common/http/HttpConnection.java
index f837274e79..81bb6a68b4 100644
--- a/src/main/java/com/tencentcloudapi/common/http/HttpConnection.java
+++ b/src/main/java/com/tencentcloudapi/common/http/HttpConnection.java
@@ -56,11 +56,6 @@ public void setProxyAuthenticator(Authenticator authenticator) {
         this.client = this.client.newBuilder().proxyAuthenticator(authenticator).build();
     }
 
-    @Deprecated
-    public void setSSLSocketFactory(SSLSocketFactory sslSocketFactory) {
-        this.client = this.client.newBuilder().sslSocketFactory(sslSocketFactory).build();
-    }
-
     public void setSSLSocketFactory(SSLSocketFactory sslSocketFactory, X509TrustManager trustManager) {
         this.client = this.client.newBuilder().sslSocketFactory(sslSocketFactory, trustManager).build();
     }
@@ -99,7 +94,7 @@ public Response postRequest(String url, String body) throws TencentCloudSDKExcep
         MediaType contentType = MediaType.parse("application/x-www-form-urlencoded");
         Request request = null;
         try {
-            request = new Request.Builder().url(url).post(RequestBody.create(contentType, body)).build();
+            request = new Request.Builder().url(url).post(RequestBody.create(body, contentType)).build();
         } catch (IllegalArgumentException e) {
             throw new TencentCloudSDKException(e.getClass().getName() + "-" + e.getMessage());
         }
@@ -115,7 +110,7 @@ public Response postRequest(String url, String body, Headers headers)
             request =
                     new Request.Builder()
                             .url(url)
-                            .post(RequestBody.create(contentType, body))
+                            .post(RequestBody.create(body, contentType))
                             .headers(headers)
                             .build();
         } catch (IllegalArgumentException e) {
@@ -133,7 +128,7 @@ public Response postRequest(String url, byte[] body, Headers headers)
             request =
                     new Request.Builder()
                             .url(url)
-                            .post(RequestBody.create(contentType, body))
+                            .post(RequestBody.create(body, contentType))
                             .headers(headers)
                             .build();
         } catch (IllegalArgumentException e) {
diff --git a/src/test/java/com/tencentcloudapi/integration/commonclient/OkhttpUpgradeTest.java b/src/test/java/com/tencentcloudapi/integration/commonclient/OkhttpUpgradeTest.java
new file mode 100644
index 0000000000..c310a8850e
--- /dev/null
+++ b/src/test/java/com/tencentcloudapi/integration/commonclient/OkhttpUpgradeTest.java
@@ -0,0 +1,161 @@
+package com.tencentcloudapi.integration.commonclient;
+
+import com.tencentcloudapi.common.CommonClient;
+import com.tencentcloudapi.common.Credential;
+import com.tencentcloudapi.common.exception.TencentCloudSDKException;
+import com.tencentcloudapi.common.profile.ClientProfile;
+import com.tencentcloudapi.common.profile.HttpProfile;
+import okhttp3.OkHttp;
+import org.junit.Assert;
+import org.junit.Test;
+
+import javax.net.ssl.SSLContext;
+import javax.net.ssl.SSLSocketFactory;
+import javax.net.ssl.TrustManager;
+import javax.net.ssl.X509TrustManager;
+import java.security.KeyManagementException;
+import java.security.NoSuchAlgorithmException;
+import java.security.cert.X509Certificate;
+
+/**
+ * 验证 okhttp 升级到 4.x 后核心功能正常
+ * 运行前请设置环境变量:
+ *   TENCENTCLOUD_SECRET_ID
+ *   TENCENTCLOUD_SECRET_KEY
+ */
+public class OkhttpUpgradeTest {
+
+    private Credential getCredential() {
+        return new Credential(
+                System.getenv("TENCENTCLOUD_SECRET_ID"),
+                System.getenv("TENCENTCLOUD_SECRET_KEY"));
+    }
+
+    /**
+     * 验证 okhttp 版本已升级到 4.x
+     */
+    @Test
+    public void testOkhttpVersion() {
+        String version = OkHttp.VERSION;
+        System.out.println("OkHttp version: " + version);
+        Assert.assertTrue("期望 okhttp 版本为 4.x，实际为: " + version,
+                version.startsWith("4."));
+    }
+
+    /**
+     * 基础 API 调用：DescribeInstances（验证 RequestBody.create 参数顺序修改后正常）
+     */
+    @Test
+    public void testBasicApiCall() {
+        Credential cred = getCredential();
+        CommonClient client = new CommonClient("cvm", "2017-03-12", cred, "ap-guangzhou");
+        try {
+            String resp = client.call("DescribeInstances",
+                    "{\"Filters\":[{\"Name\":\"zone\",\"Values\":[\"ap-guangzhou-1\"]}]}");
+            System.out.println("DescribeInstances 响应: " + resp.substring(0, Math.min(200, resp.length())));
+            Assert.assertTrue("响应中应包含 RequestId", resp.contains("RequestId"));
+        } catch (TencentCloudSDKException e) {
+            Assert.fail("API 调用失败: " + e.getMessage());
+        }
+    }
+
+    /**
+     * 验证 HTTPS 正常（默认 SSLSocketFactory，okhttp 4.x 默认连接）
+     */
+    @Test
+    public void testHttpsCall() {
+        Credential cred = getCredential();
+        HttpProfile httpProfile = new HttpProfile();
+        httpProfile.setProtocol("https://");
+        ClientProfile clientProfile = new ClientProfile();
+        clientProfile.setHttpProfile(httpProfile);
+
+        CommonClient client = new CommonClient("cvm", "2017-03-12", cred, "ap-guangzhou", clientProfile);
+        try {
+            String resp = client.call("DescribeInstances", "{}");
+            System.out.println("HTTPS 调用响应: " + resp.substring(0, Math.min(200, resp.length())));
+            Assert.assertTrue("HTTPS 调用应包含 RequestId", resp.contains("RequestId"));
+        } catch (TencentCloudSDKException e) {
+            Assert.fail("HTTPS 调用失败: " + e.getMessage());
+        }
+    }
+
+    /**
+     * 验证仅设置 SSLSocketFactory（不传 TrustManager）时 okhttp 4.x 兼容性
+     * AbstractClient 改动：自动获取默认 X509TrustManager，避免报错
+     */
+    @Test
+    public void testSSLSocketFactoryOnlyCompat() throws NoSuchAlgorithmException, KeyManagementException {
+        Credential cred = getCredential();
+
+        // 只创建 SSLSocketFactory，不显式传 TrustManager（模拟旧调用方式）
+        SSLContext sslContext = SSLContext.getInstance("TLS");
+        sslContext.init(null, null, null); // 使用 JVM 默认 TrustManager
+        SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();
+
+        HttpProfile httpProfile = new HttpProfile();
+        httpProfile.setSslSocketFactory(sslSocketFactory);
+        // 注意：不调用 setX509TrustManager，测试 AbstractClient 的自动兜底逻辑
+        ClientProfile clientProfile = new ClientProfile();
+        clientProfile.setHttpProfile(httpProfile);
+
+        CommonClient client = new CommonClient("cvm", "2017-03-12", cred, "ap-guangzhou", clientProfile);
+        try {
+            String resp = client.call("DescribeInstances", "{}");
+            System.out.println("SSLSocketFactory-only 调用响应: " + resp.substring(0, Math.min(200, resp.length())));
+            Assert.assertTrue("应包含 RequestId", resp.contains("RequestId"));
+        } catch (TencentCloudSDKException e) {
+            Assert.fail("SSLSocketFactory only 调用失败（兼容性回归）: " + e.getMessage());
+        }
+    }
+
+    /**
+     * 验证自定义 SSLSocketFactory + TrustManager（信任所有证书）调用正常
+     */
+    @Test
+    public void testCustomSSLSocketFactory() throws Exception {
+        Credential cred = getCredential();
+
+        TrustManager[] trustAllCerts = new TrustManager[]{
+                new X509TrustManager() {
+                    public void checkClientTrusted(X509Certificate[] chain, String authType) {}
+                    public void checkServerTrusted(X509Certificate[] chain, String authType) {}
+                    public X509Certificate[] getAcceptedIssuers() { return new X509Certificate[0]; }
+                }
+        };
+        SSLContext sslContext = SSLContext.getInstance("TLS");
+        sslContext.init(null, trustAllCerts, new java.security.SecureRandom());
+        SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();
+
+        HttpProfile httpProfile = new HttpProfile();
+        httpProfile.setSslSocketFactory(sslSocketFactory);
+        httpProfile.setX509TrustManager((X509TrustManager) trustAllCerts[0]);
+        ClientProfile clientProfile = new ClientProfile();
+        clientProfile.setHttpProfile(httpProfile);
+
+        CommonClient client = new CommonClient("cvm", "2017-03-12", cred, "ap-guangzhou", clientProfile);
+        try {
+            String resp = client.call("DescribeInstances", "{}");
+            System.out.println("自定义 SSL 调用响应: " + resp.substring(0, Math.min(200, resp.length())));
+            Assert.assertTrue("应包含 RequestId", resp.contains("RequestId"));
+        } catch (TencentCloudSDKException e) {
+            Assert.fail("自定义 SSL 调用失败: " + e.getMessage());
+        }
+    }
+
+    /**
+     * 验证 POST JSON 请求（覆盖 RequestBody.create(body, contentType) 调用路径）
+     */
+    @Test
+    public void testPostJsonRequest() {
+        Credential cred = getCredential();
+        CommonClient client = new CommonClient("sts", "2018-08-13", cred, "ap-guangzhou");
+        try {
+            String resp = client.call("GetCallerIdentity", "{}");
+            System.out.println("GetCallerIdentity 响应: " + resp.substring(0, Math.min(200, resp.length())));
+            Assert.assertTrue("应包含 RequestId", resp.contains("RequestId"));
+        } catch (TencentCloudSDKException e) {
+            Assert.fail("POST JSON 请求失败: " + e.getMessage());
+        }
+    }
+}