diff --git a/electrumx/server/rate_limiter.py b/electrumx/server/rate_limiter.py
index 975d239..8a54e06 100644
--- a/electrumx/server/rate_limiter.py
+++ b/electrumx/server/rate_limiter.py
@@ -334,8 +334,21 @@ def _header(session, name: str) -> Optional[str]:
         """Best-effort read of a request header from a (WS) session/transport.
 
         Supports several shapes so tests and the live WS transport both work:
-        ``session.request_headers``, ``session.transport.websocket.request_headers``
-        and a plain ``session.headers`` mapping.  Returns None if unavailable.
+        ``session.request_headers``, ``session.transport.websocket.request_headers``,
+        ``…websocket.request.headers`` and a plain ``session.headers`` mapping.
+        Returns None if unavailable.
+
+        The two websocket shapes are a library-version split, and getting it
+        wrong fails *silently* rather than loudly — which is why both are
+        covered here. ``websockets.serve`` resolves to the legacy asyncio
+        server below 14 and to ``websockets.asyncio.server`` from 14 on, and
+        the new server does not carry ``request_headers`` at all; the handshake
+        request moved to ``websocket.request``. Since this helper falls back to
+        None on a missing attribute, a version bump alone would leave
+        X-Forwarded-For permanently unresolved: with TRUST_PROXY on, every
+        client would collapse onto the proxy's own address and share one
+        rate-limit bucket. Verified against 13.1 (``request_headers`` present,
+        ``request`` absent) and 16.1 (the reverse).
         """
         candidates = []
         for obj in (session, getattr(session, 'transport', None)):
@@ -344,6 +357,8 @@ def _header(session, name: str) -> Optional[str]:
             ws = getattr(obj, 'websocket', None)
             if ws is not None:
                 candidates.append(getattr(ws, 'request_headers', None))
+                candidates.append(
+                    getattr(getattr(ws, 'request', None), 'headers', None))
             candidates.append(getattr(obj, 'request_headers', None))
             candidates.append(getattr(obj, 'headers', None))
         for headers in candidates:
diff --git a/requirements-ci.txt b/requirements-ci.txt
index 46e125c..b7717cf 100644
--- a/requirements-ci.txt
+++ b/requirements-ci.txt
@@ -3,7 +3,15 @@ attrs
 plyvel
 pylru
 aiohttp>=3.3,<4.0
-websockets>=10.0,<16.0
+# Must track requirements.txt exactly. websockets 14 swapped `websockets.serve`
+# from the legacy asyncio server to websockets.asyncio.server, and the two
+# expose the handshake differently (legacy: connection.request_headers; new:
+# connection.request.headers). This file used to allow <16.0 while the runtime
+# pinned <14.0, so CI resolved 15.0.1 against a production that runs 13.1 —
+# i.e. CI exercised a different websockets implementation than the server
+# actually uses, on the exact axis where they diverge. Bump both together,
+# deliberately, not one as a side effect.
+websockets>=10.0,<14.0
 psutil
 cbor2>=5.4.0
 
diff --git a/tests/server/test_ip_rate_limiter.py b/tests/server/test_ip_rate_limiter.py
index 7839660..02ba39e 100644
--- a/tests/server/test_ip_rate_limiter.py
+++ b/tests/server/test_ip_rate_limiter.py
@@ -656,3 +656,93 @@ def test_connection_cap_blocked_ip_refused():
     allowed, reason = rl.check_can_register(ip, now=1000.0)
     assert allowed is False
     assert 'blocked' in reason
+
+
+# --------------------------------------------------------------------------- #
+# Header discovery across websockets-library shapes.
+#
+# `websockets.serve` resolves to the legacy asyncio server below 14 and to
+# websockets.asyncio.server from 14 on. The legacy connection exposes
+# `request_headers`; the new one does NOT -- the handshake request moved to
+# `connection.request`, with headers underneath it. Verified live against 13.1
+# (request_headers present, request absent) and 16.1 (the reverse).
+#
+# _header falls back to None on a missing attribute, so a websockets upgrade
+# alone would not raise -- X-Forwarded-For would just never resolve again, and
+# with TRUST_PROXY on every client would collapse onto the proxy's own address
+# and share a single rate-limit bucket. These pin both shapes so the upgrade
+# cannot regress it silently.
+# --------------------------------------------------------------------------- #
+
+class _FakeRequest:
+    """websockets >=14: connection.request.headers."""
+
+    def __init__(self, headers):
+        self.headers = _FakeHeaders(headers)
+
+
+class _FakeWSLegacy:
+    """websockets <14: connection.request_headers."""
+
+    def __init__(self, headers):
+        self.request_headers = _FakeHeaders(headers)
+
+
+class _FakeWSNew:
+    def __init__(self, headers):
+        self.request = _FakeRequest(headers)
+
+
+class _FakeTransport:
+    def __init__(self, websocket):
+        self.websocket = websocket
+
+
+class _WSSession:
+    """A session whose headers are reachable only via transport.websocket,
+    as with the live WS transport (see HTTPTransport in httpserver.py)."""
+
+    def __init__(self, websocket, peer_host='127.0.0.1', port=50002):
+        self.transport = _FakeTransport(websocket)
+        self._peer = NetAddress(peer_host, port)
+        self.session_id = 0
+        self.client_ip = None
+
+    def remote_address(self):
+        return self._peer
+
+
+def test_xff_via_legacy_websocket_shape():
+    rl = IPRateLimiter(_env(trust_proxy=True, trust_proxy_hops=1))
+    sess = _WSSession(_FakeWSLegacy({'X-Forwarded-For': '203.0.113.7'}))
+    assert rl.client_ip(sess) == '203.0.113.7'
+
+
+def test_xff_via_new_websocket_request_shape():
+    """websockets >=14: headers live at connection.request.headers."""
+    rl = IPRateLimiter(_env(trust_proxy=True, trust_proxy_hops=1))
+    sess = _WSSession(_FakeWSNew({'X-Forwarded-For': '203.0.113.7'}))
+    assert rl.client_ip(sess) == '203.0.113.7'
+
+
+def test_x_real_ip_via_new_websocket_request_shape():
+    rl = IPRateLimiter(_env(trust_proxy=True))
+    sess = _WSSession(_FakeWSNew({'X-Real-IP': '203.0.113.42'}))
+    assert rl.client_ip(sess) == '203.0.113.42'
+
+
+def test_new_shape_multi_hop_selection():
+    rl = IPRateLimiter(_env(trust_proxy=True, trust_proxy_hops=2))
+    sess = _WSSession(_FakeWSNew(
+        {'X-Forwarded-For': '203.0.113.7, 198.51.100.9, 10.0.0.1'}))
+    assert rl.client_ip(sess) == '198.51.100.9'
+
+
+def test_websocket_without_either_shape_falls_back_to_peer():
+    """A connection object exposing neither attribute must degrade to the
+    socket peer rather than raising."""
+    class _Bare:
+        pass
+    rl = IPRateLimiter(_env(trust_proxy=True))
+    sess = _WSSession(_Bare(), peer_host='8.8.8.8')
+    assert rl.client_ip(sess) == '8.8.8.8'