diff --git a/docs/sphinx/source/en/2-user_guide/3-backends/7-newton.md b/docs/sphinx/source/en/2-user_guide/3-backends/7-newton.md
index 07cbd0d7a..1de946d91 100644
--- a/docs/sphinx/source/en/2-user_guide/3-backends/7-newton.md
+++ b/docs/sphinx/source/en/2-user_guide/3-backends/7-newton.md
@@ -33,8 +33,10 @@ collector sim processes land on their own physical GPU with no cross-GPU
 leakage; single-GPU PPO/SAC regressions pass alongside. Newton/Warp follows
 standard CUDA device semantics, so no `CUDA_VISIBLE_DEVICES` pinning (the
 Genesis quirk) is needed; the rank-local device reaches spawn collectors as
-a `newton_device="cuda:N"` env override (uni_rl 1.0.0's collector-side
-process-binding gate only covers mjwarp), and the SAC owner raises the
+a `newton_device="cuda:N"` env override, and uni_rl's collector-side
+process binding is injection-based — UniLab injects
+`bind_backend_process_device_for_backend`, which covers both mjwarp and
+newton — while the SAC owner raises the
 collector tick-0 timeout to 180 s to cover Warp kernel compilation on the
 cold path.
 
diff --git a/docs/sphinx/source/zh_CN/2-user_guide/3-backends/7-newton.md b/docs/sphinx/source/zh_CN/2-user_guide/3-backends/7-newton.md
index 6e3f42e1f..6c57cbe58 100644
--- a/docs/sphinx/source/zh_CN/2-user_guide/3-backends/7-newton.md
+++ b/docs/sphinx/source/zh_CN/2-user_guide/3-backends/7-newton.md
@@ -31,9 +31,10 @@ DpRankSupervisor DP=2（`training.devices=[0,1]`）训练冒烟均正常完成
 在各自 GPU、无对端泄漏；单卡 PPO/SAC 回归同步通过。Newton/Warp 遵循标准
 CUDA 设备语义，无需 Genesis 那样的 `CUDA_VISIBLE_DEVICES` 钉卡；rank
 本地设备通过 env override 以 `newton_device="cuda:N"` 传入 spawn
-collector（uni_rl 1.0.0 的 collector 进程绑定门只覆盖 mjwarp），SAC
-owner 将 collector tick-0 超时提升到 180 s 以覆盖 Warp 内核编译的冷
-路径。
+collector，且 uni_rl 的 collector 进程绑定为注入式——UniLab 注入的
+`bind_backend_process_device_for_backend` 同时覆盖 mjwarp 与
+newton；SAC owner 将 collector tick-0 超时提升到 180 s 以覆盖 Warp
+内核编译的冷路径。
 
 ## 安装
 
diff --git a/pyproject.toml b/pyproject.toml
index ebaa70f21..5637d1bfe 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -170,7 +170,7 @@ viser = ["viser>=1.0.26", "trimesh>=3.21.7"]
 # required-environments; elsewhere the extra is empty and the CLI reports a
 # targeted runtime diagnostic.
 superdex = [
-    "unisim-core[superdex]>=1.4.0 ; python_version >= '3.12' and sys_platform == 'linux' and platform_machine == 'x86_64'",
+    "unisim-core[superdex]>=1.4.2 ; python_version >= '3.12' and sys_platform == 'linux' and platform_machine == 'x86_64'",
 ]
 
 [dependency-groups]
diff --git a/scripts/benchmark/rl/benchmark_replay_buffer_placement.py b/scripts/benchmark/rl/benchmark_replay_buffer_placement.py
index e98fcc82c..4010c0592 100644
--- a/scripts/benchmark/rl/benchmark_replay_buffer_placement.py
+++ b/scripts/benchmark/rl/benchmark_replay_buffer_placement.py
@@ -191,6 +191,12 @@ def _xpu_available() -> bool:
 
 
 def _replay_transfer_manifest(device: torch.device, *, ring_depth: int = 2) -> dict[str, Any]:
+    """Describe the uni_rl 1.2.1 replay-transfer backend for ``device``.
+
+    uni_rl 1.2.1 builds ``CudaLikeReplayTransferBackend`` for CUDA (ROCm
+    included) and ``TorchCopyReplayTransferBackend`` otherwise; the async
+    ``submit_h2d`` path and the dedicated XPU backend no longer exist.
+    """
     if device.type == "cuda":
         torch_version = getattr(torch, "version", None)
         is_rocm = bool(getattr(torch_version, "hip", None))
@@ -198,26 +204,14 @@ def _replay_transfer_manifest(device: torch.device, *, ring_depth: int = 2) -> d
             "backend": "CudaLikeReplayTransferBackend",
             "device_family": "rocm" if is_rocm else "cuda",
             "host_memory_kind": "registered_pinned_shared",
-            "supports_async_submit": True,
             "supports_timing_events": True,
             "h2d_submitter": "torch_copy_stream" if is_rocm else "pybind11",
             "ring_depth": ring_depth,
         }
-    if device.type == "xpu":
-        return {
-            "backend": "XpuReplayTransferBackend",
-            "device_family": "xpu",
-            "host_memory_kind": "pageable_shared",
-            "supports_async_submit": True,
-            "supports_timing_events": False,
-            "h2d_submitter": "torch_xpu_copy_stream",
-            "ring_depth": ring_depth,
-        }
     return {
         "backend": "TorchCopyReplayTransferBackend",
         "device_family": device.type,
         "host_memory_kind": "pageable_shared",
-        "supports_async_submit": False,
         "supports_timing_events": False,
         "h2d_submitter": "torch_copy",
         "ring_depth": ring_depth,
diff --git a/src/unilab/base/backend_factory.py b/src/unilab/base/backend_factory.py
index 5976cd478..f4ffa1676 100644
--- a/src/unilab/base/backend_factory.py
+++ b/src/unilab/base/backend_factory.py
@@ -22,25 +22,6 @@
     from unilab.base.scene import SceneCfg
 
 
-def _legacy_genesis_device_option_error(exc: TypeError) -> bool:
-    """Identify an old UniSim adapter rejecting the optional device keyword.
-
-    UniSim 1.1 reports unknown backend options from ``GenesisBackend`` while
-    other compatible releases may expose Python's usual ``unexpected keyword``
-    wording.  Keep the compatibility retry narrowly scoped to those messages;
-    constructor errors from the actual Genesis runtime must still propagate.
-    """
-
-    message = str(exc).lower()
-    mentions_device = "genesis_device_id" in message or "device_id" in message
-    rejects_keyword = (
-        "does not accept backend options" in message
-        or "unexpected keyword argument" in message
-        or "unexpected keyword" in message
-    )
-    return mentions_device and rejects_keyword
-
-
 def env_backend_kwargs(cfg: "EnvCfg") -> dict[str, Any]:
     """Translate ``EnvCfg`` backend knobs into UniSim adapter options."""
     result: dict[str, Any] = {
@@ -69,18 +50,13 @@ def env_backend_kwargs(cfg: "EnvCfg") -> dict[str, Any]:
         "isaacsim_render_mode": cfg.isaacsim_render_mode,
         "isaacsim_render_width": cfg.isaacsim_render_width,
         "isaacsim_render_height": cfg.isaacsim_render_height,
+        "superdex_execution_mode": cfg.superdex_execution_mode,
     }
-    # Keep the optional key absent for legacy unisim-core releases that do not
-    # know about Genesis' explicit device argument.  Once a rank selects a
-    # device the key is added below and ``create_backend`` supplies a narrow
-    # compatibility fallback for those releases.
+    # Forward the explicit Genesis device id only when a rank selected one;
+    # when absent, unisim-core's factory default applies and Genesis picks
+    # its own device.
     if cfg.genesis_device_id is not None:
         result["genesis_device_id"] = cfg.genesis_device_id
-    # Keep the default absent so unisim-core releases that predate the
-    # execution-mode option still accept the SuperDex kwargs; "serial" requires
-    # the updated adapter.
-    if cfg.superdex_execution_mode != "batch":
-        result["superdex_execution_mode"] = cfg.superdex_execution_mode
     return result
 
 
@@ -112,17 +88,6 @@ def create_backend(
     ensure_robot_assets_for_paths(
         [scene.model_file, scene.visual_model_file, *scene.fragment_files]
     )
-    if backend_type != "newton":
-        # Keep the owner translation forward-compatible with unisim-core
-        # releases that predate the Newton adapter and therefore do not pop
-        # these optional kwargs in their shared factory.
-        for key in (
-            "newton_device",
-            "newton_nconmax",
-            "newton_njmax",
-            "newton_capacity_check_steps",
-        ):
-            kwargs.pop(key, None)
     if backend_type == "drake":
         # unisim-core 1.4.2 dropped the Drake-branch filtering of MuJoCo
         # root-body options; Drake derives root state from its own plant and
@@ -139,11 +104,9 @@ def create_backend(
     }
     if backend_type == "genesis" and kwargs.get("genesis_device_id") is not None:
         # Bind before any unisim-core Genesis constructor can call gs.init.
-        # New unisim-core releases repeat this idempotently; old releases do
-        # not accept the keyword, so the retry below still gets the correct
-        # process-wide device.  Binding a non-zero id pins
-        # CUDA_VISIBLE_DEVICES (Quadrants only honors the first visible
-        # device), so forward the *post-pin* in-process index.
+        # Binding a non-zero id pins CUDA_VISIBLE_DEVICES (Quadrants only
+        # honors the first visible device), so forward the *post-pin*
+        # in-process index.
         genesis_device_id = kwargs["genesis_device_id"]
         if (
             isinstance(genesis_device_id, bool)
@@ -156,19 +119,7 @@ def create_backend(
             )
         bound = bind_genesis_process_device(f"cuda:{genesis_device_id}")
         kwargs["genesis_device_id"] = int(bound.rsplit(":", 1)[1])
-    try:
-        return unisim.create_backend(backend_type, scene, num_envs, sim_dt, **kwargs)
-    except TypeError as exc:
-        if backend_type != "genesis" or "genesis_device_id" not in kwargs:
-            raise
-        # unisim-core < 1.2 has no Genesis device field and reports the
-        # unknown option from GenesisBackend.  Retry only for that precise
-        # capability error; unrelated constructor TypeErrors must propagate.
-        if not _legacy_genesis_device_option_error(exc):
-            raise
-        legacy_kwargs = dict(kwargs)
-        legacy_kwargs.pop("genesis_device_id", None)
-        return unisim.create_backend(backend_type, scene, num_envs, sim_dt, **legacy_kwargs)
+    return unisim.create_backend(backend_type, scene, num_envs, sim_dt, **kwargs)
 
 
 __all__ = ["SimBackend", "create_backend", "env_backend_kwargs"]
diff --git a/src/unilab/base/env_factory.py b/src/unilab/base/env_factory.py
index 46c256714..20f8f70b5 100644
--- a/src/unilab/base/env_factory.py
+++ b/src/unilab/base/env_factory.py
@@ -42,9 +42,11 @@ def make_registry_env(
     # carry the explicit cold-path id in the opaque override and bind
     # immediately before registry construction.  Binding a non-zero id pins
     # CUDA_VISIBLE_DEVICES for this process, so forward the post-pin
-    # in-process index downstream.  Newer unisim-core versions repeat this
-    # check in GenesisBackend itself, making this compatibility guard
-    # idempotent.
+    # in-process index downstream.  This binding is required, not a
+    # compatibility shim: spawn collectors are fresh interpreters that cannot
+    # inherit the parent process's binding, and only UniLab's
+    # ``bind_genesis_process_device`` sets the pinned-namespace flag its
+    # resolution helpers consult.
     if sim_backend == "genesis" and env_cfg_override is not None:
         genesis_device_id = env_cfg_override.get("genesis_device_id")
         if genesis_device_id is not None:
diff --git a/src/unilab/base/process_device.py b/src/unilab/base/process_device.py
index ee30357c1..37ab1e0d4 100644
--- a/src/unilab/base/process_device.py
+++ b/src/unilab/base/process_device.py
@@ -26,9 +26,12 @@
 
 
 # Newton consumes an explicit ``cuda:N`` device string (``newton_device``)
-# instead of an integer id.  uni_rl's collector-side binder gate only knows
-# mjwarp, so the rank-local device must reach spawn collectors through the
-# env override rather than through process binding.
+# instead of an integer id.  uni_rl's collector-side process binding is
+# injection-based: it binds through the caller-supplied ``bind_device``
+# callable and fails closed when none is injected.  UniLab injects
+# ``bind_backend_process_device_for_backend`` (which covers mjwarp and
+# newton); the env override additionally forwards the rank-local device
+# string so spawn collectors can pass it to the Newton adapter.
 BACKEND_ENV_DEVICE_STR_FIELDS: dict[str, str] = {
     "newton": "newton_device",
 }
diff --git a/src/unilab/cli.py b/src/unilab/cli.py
index 926eb2bae..e7fd7944d 100644
--- a/src/unilab/cli.py
+++ b/src/unilab/cli.py
@@ -133,13 +133,7 @@ def _check_runtime_requirements(algo: str, sim: str) -> None:
                 "in a source checkout (or `pip install unilab[newton]`)."
             )
     if sim == "superdex":
-        try:
-            from unisim.backend.superdex.dependencies import superdex_dependencies_available
-        except ImportError as exc:
-            raise SystemExit(
-                "sim=superdex requires unisim-core>=1.1.5 with the SuperDex adapter; "
-                "the installed unisim-core does not provide that adapter."
-            ) from exc
+        from unisim.backend.superdex.dependencies import superdex_dependencies_available
 
         if not superdex_dependencies_available():
             raise SystemExit(
diff --git a/tests/base/backend/test_process_device.py b/tests/base/backend/test_process_device.py
index 8c51b61f3..7c1b693f9 100644
--- a/tests/base/backend/test_process_device.py
+++ b/tests/base/backend/test_process_device.py
@@ -170,8 +170,8 @@ def test_non_gpu_backend_is_left_untouched() -> None:
 
 
 def test_newton_override_carries_cuda_device_string() -> None:
-    # uni_rl's collector binder gate only knows mjwarp, so newton's rank-local
-    # device must reach spawn collectors as a ``cuda:N`` override string.
+    # Newton consumes an explicit ``cuda:N`` string, so its rank-local device
+    # reaches spawn collectors as an override string rather than an integer id.
     owner_override: dict[str, object] = {"newton_device": None, "nested": {"keep": True}}
     routed = apply_backend_env_device_override(
         owner_override,
diff --git a/tests/base/test_superdex_backend_options.py b/tests/base/test_superdex_backend_options.py
index 8adc2df69..7d15f306f 100644
--- a/tests/base/test_superdex_backend_options.py
+++ b/tests/base/test_superdex_backend_options.py
@@ -93,7 +93,7 @@ def create(name: str, scene: SceneCfg, num_envs: int, dt: float, **kwargs: Any)
     assert captured["superdex_num_workers"] == workers
 
 
-def test_superdex_execution_mode_is_forwarded_only_when_serial(
+def test_superdex_execution_mode_is_always_forwarded(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
     captured: dict[str, Any] = {}
@@ -111,13 +111,11 @@ def create(name: str, scene: SceneCfg, num_envs: int, dt: float, **kwargs: Any)
     backend_factory.create_backend(
         "superdex", scene, 1, 0.002, **backend_factory.env_backend_kwargs(serial)
     )
-    # Legacy unisim-core releases predate the option; the default stays absent
-    # so they still accept the SuperDex kwargs.
     assert captured["superdex_execution_mode"] == "serial"
     backend_factory.create_backend(
         "superdex", scene, 1, 0.002, **backend_factory.env_backend_kwargs(EnvCfg())
     )
-    assert "superdex_execution_mode" not in captured
+    assert captured["superdex_execution_mode"] == "batch"
 
 
 def test_superdex_execution_mode_validates_and_does_not_leak(
diff --git a/tests/benchmark/test_replay_buffer_placement_benchmark.py b/tests/benchmark/test_replay_buffer_placement_benchmark.py
index 4b2ce02c7..6ba406cdc 100644
--- a/tests/benchmark/test_replay_buffer_placement_benchmark.py
+++ b/tests/benchmark/test_replay_buffer_placement_benchmark.py
@@ -133,7 +133,7 @@ def test_replay_transfer_manifest_records_backend_fields() -> None:
     assert manifest["backend"] == "TorchCopyReplayTransferBackend"
     assert manifest["device_family"] == "cpu"
     assert manifest["host_memory_kind"] == "pageable_shared"
-    assert manifest["supports_async_submit"] is False
+    assert "supports_async_submit" not in manifest
     assert manifest["ring_depth"] == 2
 
 
diff --git a/tests/test_cli_runtime_requirements.py b/tests/test_cli_runtime_requirements.py
index de8fbb7af..b4c79390e 100644
--- a/tests/test_cli_runtime_requirements.py
+++ b/tests/test_cli_runtime_requirements.py
@@ -62,13 +62,3 @@ def test_superdex_missing_runtime_reports_python_and_sdk(monkeypatch: pytest.Mon
         SystemExit, match=r"Python 3\.12.*Physics/Robotics.*uv sync --extra superdex"
     ):
         cli._check_runtime_requirements("ppo", "superdex")
-
-
-def test_superdex_old_unisim_reports_adapter_requirement(
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    import sys
-
-    monkeypatch.setitem(sys.modules, "unisim.backend.superdex.dependencies", None)
-    with pytest.raises(SystemExit, match="unisim-core>=1.1.5 with the SuperDex adapter"):
-        cli._check_runtime_requirements("ppo", "superdex")
diff --git a/uv.lock b/uv.lock
index d21cbaa7e..d6919a5a9 100644
--- a/uv.lock
+++ b/uv.lock
@@ -5241,7 +5241,7 @@ requires-dist = [
     { name = "typing-extensions" },
     { name = "unilab-rl", specifier = "==1.2.1" },
     { name = "unisim-core", specifier = ">=1.4.2" },
-    { name = "unisim-core", extras = ["superdex"], marker = "python_full_version >= '3.12' and platform_machine == 'x86_64' and sys_platform == 'linux' and extra == 'superdex'", specifier = ">=1.4.0" },
+    { name = "unisim-core", extras = ["superdex"], marker = "python_full_version >= '3.12' and platform_machine == 'x86_64' and sys_platform == 'linux' and extra == 'superdex'", specifier = ">=1.4.2" },
     { name = "viser", marker = "extra == 'viser'", specifier = ">=1.0.26" },
     { name = "wandb" },
     { name = "warp-lang", marker = "extra == 'mjwarp'", specifier = "==1.16.0" },