diff --git a/include/xlnt/utils/optional.hpp b/include/xlnt/utils/optional.hpp
index 4f56c812..757c90ea 100644
--- a/include/xlnt/utils/optional.hpp
+++ b/include/xlnt/utils/optional.hpp
@@ -53,8 +53,8 @@ class optional
     /// <summary>
     /// Default equality operation, just uses operator==
     /// </summary>
-    template <typename T, typename std::enable_if<!std::is_floating_point_v<T>>::type * = nullptr>
-    constexpr bool compare_equal(const T &lhs, const T &rhs) const
+    template <typename U = T, typename std::enable_if<!std::is_floating_point<U>::value>::type * = nullptr>
+    constexpr bool compare_equal(const U &lhs, const U &rhs) const
     {
         return lhs == rhs;
     }
@@ -62,8 +62,8 @@ class optional
     /// <summary>
     /// equality operation for floating point numbers. Provides "fuzzy" equality
     /// </summary>
-    template <typename T, typename std::enable_if<std::is_floating_point_v<T>>::type * = nullptr>
-    constexpr bool compare_equal(const T &lhs, const T &rhs) const
+    template <typename U = T, typename std::enable_if<std::is_floating_point<U>::value>::type * = nullptr>
+    constexpr bool compare_equal(const U &lhs, const U &rhs) const
     {
         return detail::float_equals(lhs, rhs);
     }
diff --git a/source/detail/numeric_utils.hpp b/source/detail/numeric_utils.hpp
index 737992f5..2e3a0de9 100644
--- a/source/detail/numeric_utils.hpp
+++ b/source/detail/numeric_utils.hpp
@@ -90,7 +90,7 @@ float_equals(const LNumber &lhs, const RNumber &rhs,
         return false;
     }
     // a type that lhs and rhs can agree on
-    using common_t = std::common_type_t<LNumber, RNumber>;
+    using common_t = std::common_type<LNumber, RNumber>::type;
     // epsilon type defaults to float because even if both args are a higher precision type
     // either or both could have been promoted by prior operations
     // if a higher precision is required, the template type can be changed