diff --git a/modern_di_grpc/main.py b/modern_di_grpc/main.py
index 01d191e..4894343 100644
--- a/modern_di_grpc/main.py
+++ b/modern_di_grpc/main.py
@@ -42,7 +42,7 @@ def fetch_di_container() -> Container:
 
 def _ensure_context_provider(container: Container) -> None:
     # Register grpc_context_provider once (idempotent) so ServicerContext injects out of the box.
-    if container.providers_registry.find_provider(ServicerContext) is None:
+    if container.find_provider(ServicerContext) is None:
         container.add_providers(grpc_context_provider)
 
 
diff --git a/pyproject.toml b/pyproject.toml
index aaf5b69..38b778a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,7 +19,7 @@ classifiers = [
 dependencies = [
     # The committed test stubs under tests/protos refuse to import below 1.82.1.
     "grpcio>=1.82.1,<2",
-    "modern-di>=3.1,<4",
+    "modern-di>=4,<5",
 ]
 version = "0"
 
diff --git a/tests/dependencies.py b/tests/dependencies.py
index cc2a05d..92fd484 100644
--- a/tests/dependencies.py
+++ b/tests/dependencies.py
@@ -24,8 +24,7 @@ class ContextReader:
 
 
 def _make_context_reader(context: ServicerContext | None = None) -> ContextReader:
-    # `context` is wired from grpc_context_provider (ContextProvider(ServicerContext, REQUEST));
-    # the `| None = None` default lets it construct at validate time when no context is set.
+    # The default applies only when no DIInterceptor has registered grpc_context_provider on the container.
     return ContextReader(peer=context.peer() if context is not None else "no-context")
 
 
diff --git a/tests/test_inject.py b/tests/test_inject.py
index b2488b5..5c37377 100644
--- a/tests/test_inject.py
+++ b/tests/test_inject.py
@@ -189,7 +189,7 @@ def behavior(_request: object, _context: ServicerContext) -> str:
 def test_di_interceptor_registers_context_provider_idempotently() -> None:
     container = Container(groups=[Dependencies])
     DIInterceptor(container)
-    assert container.providers_registry.find_provider(ServicerContext) is not None
+    assert container.find_provider(ServicerContext) is not None
     # Second construction on the same container must hit the idempotent-skip branch, not
     # try (and fail) to register grpc_context_provider a second time.
     DIInterceptor(container)