fix: enhance retry mechanism for network-level timeouts in AuthInterceptor and OAuthInterceptor; update version to 1.11.2

Author: reeshika-h

changelog.md

@@ -5,6 +5,7 @@
 ### Jun 01, 2026
 
 - Fix: `SocketTimeoutException` now correctly triggers the retry mechanism in `AuthInterceptor` and `OAuthInterceptor`. Previously, network-level timeouts bypassed retry logic entirely, causing `.setRetry(true)` to have no effect on timeout errors.
+- Enhancement: Added `setProtocols(List<Protocol>)` to the Builder, allowing callers to restrict the HTTP protocol (e.g. force HTTP/1.1 via `Collections.singletonList(Protocol.HTTP_1_1)`) for environments where proxies or intermediaries have issues with HTTP/2.
 
 ## v1.11.1
 

src/main/java/com/contentstack/cms/Contentstack.java

@@ -3,7 +3,9 @@
 import java.io.IOException;
 import java.net.Proxy;
 import java.time.Duration;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
@@ -30,6 +32,7 @@
 import com.contentstack.cms.core.RetryConfig;
 import okhttp3.ConnectionPool;
 import okhttp3.OkHttpClient;
+import okhttp3.Protocol;
 import okhttp3.ResponseBody;
 import okhttp3.logging.HttpLoggingInterceptor;
 import retrofit2.Response;
@@ -609,6 +612,7 @@ public static class Builder {
          * evicted after 5 minutes of inactivity.
          */
         private ConnectionPool connectionPool = new ConnectionPool(); // Connection
+        private List<Protocol> protocols = null;
 
         /**
          * Instantiates a new Builder.
@@ -713,6 +717,11 @@ public Builder setConnectTimeout(int connectTimeoutSeconds) {
             return this;
         }
 
+        public Builder setProtocols(@NotNull List<Protocol> protocols) {
+            this.protocols = protocols;
+            return this;
+        }
+
         private static void validateTimeoutSeconds(int seconds, String name) {
             if (seconds <= 0) {
                 throw new IllegalArgumentException(name + " must be positive.");
@@ -881,6 +890,9 @@ private OkHttpClient httpClient(Contentstack contentstack, Boolean retryOnFailur
                     .readTimeout(Duration.ofSeconds(readSec))
                     .writeTimeout(Duration.ofSeconds(writeSec))
                     .retryOnConnectionFailure(retryOnFailure);
+            if (this.protocols != null && !this.protocols.isEmpty()) {
+                builder.protocols(this.protocols);
+            }
 
             // Add either OAuth or traditional auth interceptor
             if (this.oauthConfig != null) {

src/test/java/com/contentstack/cms/ContentstackUnitTest.java

@@ -5,6 +5,7 @@
 import com.contentstack.cms.stack.Stack;
 import okhttp3.Headers;
 import okhttp3.OkHttpClient;
+import okhttp3.Protocol;
 import okhttp3.Request;
 import okhttp3.ResponseBody;
 import okhttp3.mockwebserver.MockResponse;
@@ -17,7 +18,9 @@
 import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.net.Proxy;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
@@ -160,6 +163,24 @@ void setVersion() {
         Assertions.assertEquals("v8", contentstack.version);
     }
 
+    @Test
+    void setProtocols_http1Only_buildsSuccessfully() {
+        List<Protocol> protocols = Collections.singletonList(Protocol.HTTP_1_1);
+        Contentstack contentstack = new Contentstack.Builder()
+                .setProtocols(protocols)
+                .build();
+        Assertions.assertNotNull(contentstack);
+    }
+
+    @Test
+    void setProtocols_http2AndHttp1_buildsSuccessfully() {
+        List<Protocol> protocols = List.of(Protocol.HTTP_2, Protocol.HTTP_1_1);
+        Contentstack contentstack = new Contentstack.Builder()
+                .setProtocols(protocols)
+                .build();
+        Assertions.assertNotNull(contentstack);
+    }
+
     @Test
     void setTimeout() {
         Contentstack contentstack = new Contentstack.Builder()