diff --git a/changelog.md b/changelog.md
index 7cbd4d9..9bc711d 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 2026-03-20 - 25.17.6 - fix(rustproxy-http)
+disable HTTP/3 GREASE for client and server connections
+
+- Switch the HTTP/3 server connection setup to use the builder API with send_grease(false)
+- Switch the HTTP/3 client handshake to use the builder API with send_grease(false) to improve compatibility
+
 ## 2026-03-20 - 25.17.5 - fix(rustproxy)
 add HTTP/3 integration test for QUIC response stream FIN handling
 
diff --git a/rust/crates/rustproxy-http/src/h3_service.rs b/rust/crates/rustproxy-http/src/h3_service.rs
index 932434c..a73fb79 100644
--- a/rust/crates/rustproxy-http/src/h3_service.rs
+++ b/rust/crates/rustproxy-http/src/h3_service.rs
@@ -75,7 +75,9 @@ impl H3ProxyService {
         debug!("HTTP/3 connection from {} on port {}", remote_addr, port);
 
         let mut h3_conn: h3::server::Connection<h3_quinn::Connection, Bytes> =
-            h3::server::Connection::new(h3_quinn::Connection::new(connection))
+            h3::server::builder()
+                .send_grease(false)
+                .build(h3_quinn::Connection::new(connection))
                 .await
                 .map_err(|e| anyhow::anyhow!("H3 connection setup failed: {}", e))?;
 
diff --git a/rust/crates/rustproxy-http/src/proxy_service.rs b/rust/crates/rustproxy-http/src/proxy_service.rs
index c3e5135..3ceb18e 100644
--- a/rust/crates/rustproxy-http/src/proxy_service.rs
+++ b/rust/crates/rustproxy-http/src/proxy_service.rs
@@ -2550,7 +2550,11 @@ impl HttpProxyService {
         backend_key: &str,
     ) -> Result<Response<BoxBody<Bytes, hyper::Error>>, hyper::Error> {
         let h3_quinn_conn = h3_quinn::Connection::new(quic_conn.clone());
-        let (mut driver, mut send_request) = match h3::client::new(h3_quinn_conn).await {
+        let (mut driver, mut send_request) = match h3::client::builder()
+            .send_grease(false)
+            .build(h3_quinn_conn)
+            .await
+        {
             Ok(pair) => pair,
             Err(e) => {
                 error!(backend = %backend_key, domain = %domain, error = %e, "H3 client handshake failed");
diff --git a/ts/00_commitinfo_data.ts b/ts/00_commitinfo_data.ts
index ab4fb51..fce79e6 100644
--- a/ts/00_commitinfo_data.ts
+++ b/ts/00_commitinfo_data.ts
@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartproxy',
-  version: '25.17.5',
+  version: '25.17.6',
   description: 'A powerful proxy package with unified route-based configuration for high traffic management. Features include SSL/TLS support, flexible routing patterns, WebSocket handling, advanced security options, and automatic ACME certificate management.'
 }