diff --git a/.github/workflows/pipeline.yml b/.github/workflows/pipeline.yml
index 34c5e1ce5..454ee7a0c 100644
--- a/.github/workflows/pipeline.yml
+++ b/.github/workflows/pipeline.yml
@@ -32,6 +32,8 @@ jobs:
       uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
     - name: 'Install: MSVC'
       uses: ilammy/msvc-dev-cmd@0b201ec74fa43914dc39ae48a89fd1d8cb592756 # v1.13.0
+      with:
+        toolset: 16.0
     - name: 'Install: GCC'
       if: ${{ matrix.cxx == 'g++-13' }}
       run: |
diff --git a/include/fcarouge/internal/format.hpp b/include/fcarouge/internal/format.hpp
index 405bce16e..b79147cd0 100644
--- a/include/fcarouge/internal/format.hpp
+++ b/include/fcarouge/internal/format.hpp
@@ -58,14 +58,16 @@ template <typename State, typename Output, typename Input, typename UpdateTypes,
 struct std::formatter<
     fcarouge::kalman<State, Output, Input, UpdateTypes, PredictionTypes>,
     Char> {
+  using kalman =
+      fcarouge::kalman<State, Output, Input, UpdateTypes, PredictionTypes>;
+
   constexpr auto parse(std::basic_format_parse_context<Char> &parse_context) {
     return parse_context.begin();
   }
 
   //! @todo P2585 may be useful in simplifying and standardizing the support.
   template <typename OutputIt>
-  auto format(const fcarouge::kalman<State, Output, Input, UpdateTypes,
-                                     PredictionTypes> &filter,
+  auto format(const kalman &filter,
               std::basic_format_context<OutputIt, Char> &format_context) const
       -> OutputIt {
     format_context.advance_to(
@@ -96,7 +98,7 @@ struct std::formatter<
                                         R"("q": {}, "r": {}, "s": {}, )",
                                         filter.q(), filter.r(), filter.s()));
 
-    if constexpr (requires { filter.u(); }) {
+    if constexpr (fcarouge::has_input<kalman>) {
       format_context.advance_to(
           format_to(format_context.out(), R"("u": {}, )", filter.u()));
     }
diff --git a/include/fcarouge/internal/kalman.tpp b/include/fcarouge/internal/kalman.tpp
index 3b590587b..65e59d5d3 100644
--- a/include/fcarouge/internal/kalman.tpp
+++ b/include/fcarouge/internal/kalman.tpp
@@ -77,17 +77,19 @@ kalman<State, Output, Input, UpdateTypes, PredictionTypes>::z() const
 template <typename State, typename Output, typename Input, typename UpdateTypes,
           typename PredictionTypes>
 [[nodiscard("The returned control column vector U is unexpectedly "
-            "discarded.")]] inline constexpr auto
+            "discarded.")]] inline constexpr const auto &
 kalman<State, Output, Input, UpdateTypes, PredictionTypes>::u() const
-    -> const input &requires(requires { filter.u; }) { return filter.u; }
+  requires(has_input<implementation>)
+{
+  return filter.u;
+}
 
 template <typename State, typename Output, typename Input, typename UpdateTypes,
           typename PredictionTypes>
 [[nodiscard("The returned estimated covariance matrix P is unexpectedly "
-            "discarded.")]] inline constexpr auto kalman<State, Output, Input,
-                                                         UpdateTypes,
-                                                         PredictionTypes>::p()
-    const -> const estimate_uncertainty & {
+            "discarded.")]] inline constexpr auto
+kalman<State, Output, Input, UpdateTypes, PredictionTypes>::p() const
+    -> const estimate_uncertainty & {
   return filter.p;
 }
 
diff --git a/include/fcarouge/internal/utility.hpp b/include/fcarouge/internal/utility.hpp
index 768b31093..477da1006 100644
--- a/include/fcarouge/internal/utility.hpp
+++ b/include/fcarouge/internal/utility.hpp
@@ -52,6 +52,10 @@ concept algebraic = not arithmetic<Type>;
 template <typename Type>
 concept eigen = requires { typename Type::PlainMatrix; };
 
+template <typename Filter>
+concept has_input = requires(Filter filter) { filter.u(); } ||
+                    requires(Filter filter) { filter.u; };
+
 struct empty {
   inline constexpr explicit empty([[maybe_unused]] auto &&...any) noexcept {
     // Constructs from anything for all initializations compatibility.
diff --git a/include/fcarouge/kalman.hpp b/include/fcarouge/kalman.hpp
index 51653a446..e314d34af 100644
--- a/include/fcarouge/kalman.hpp
+++ b/include/fcarouge/kalman.hpp
@@ -346,8 +346,8 @@ class kalman final {
   //! @return The last control column vector U.
   //!
   //! @complexity Constant.
-  inline constexpr auto u() const
-      -> const input &requires(requires { filter.u; });
+  inline constexpr const auto &u() const
+    requires(has_input<implementation>);
 
   //! @brief Returns the estimated covariance matrix P.
   //!
diff --git a/include/fcarouge/utility.hpp b/include/fcarouge/utility.hpp
index 066bc3791..9a6267aa8 100644
--- a/include/fcarouge/utility.hpp
+++ b/include/fcarouge/utility.hpp
@@ -69,6 +69,13 @@ concept algebraic = internal::algebraic<Type>;
 //! @details A third party Eigen3 algebraic concept.
 template <typename Type>
 concept eigen = internal::eigen<Type>;
+
+//! @brief Filter input support concept.
+//!
+//! @details The filter supports the input related functionality: `input` type
+//! member and `u()` input method.
+template <typename Filter>
+concept has_input = internal::has_input<Filter>;
 //! @}
 
 //! @name Types