diff --git a/include/nlohmann/detail/iterators/iter_impl.hpp b/include/nlohmann/detail/iterators/iter_impl.hpp
index 434a62d3e5..d8060786ec 100644
--- a/include/nlohmann/detail/iterators/iter_impl.hpp
+++ b/include/nlohmann/detail/iterators/iter_impl.hpp
@@ -352,7 +352,7 @@ class iter_impl // NOLINT(cppcoreguidelines-special-member-functions,hicpp-speci
     @brief post-increment (it++)
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    iter_impl const operator++(int) // NOLINT(readability-const-return-type)
+    iter_impl operator++(int)& // NOLINT(cert-dcl21-cpp)
     {
         auto result = *this;
         ++(*this);
@@ -403,7 +403,7 @@ class iter_impl // NOLINT(cppcoreguidelines-special-member-functions,hicpp-speci
     @brief post-decrement (it--)
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    iter_impl const operator--(int) // NOLINT(readability-const-return-type)
+    iter_impl operator--(int)& // NOLINT(cert-dcl21-cpp)
     {
         auto result = *this;
         --(*this);
diff --git a/include/nlohmann/detail/iterators/json_reverse_iterator.hpp b/include/nlohmann/detail/iterators/json_reverse_iterator.hpp
index e787fdbcd7..65bb327a57 100644
--- a/include/nlohmann/detail/iterators/json_reverse_iterator.hpp
+++ b/include/nlohmann/detail/iterators/json_reverse_iterator.hpp
@@ -48,7 +48,7 @@ class json_reverse_iterator : public std::reverse_iterator<Base>
     explicit json_reverse_iterator(const base_iterator& it) noexcept : base_iterator(it) {}
 
     /// post-increment (it++)
-    json_reverse_iterator const operator++(int) // NOLINT(readability-const-return-type)
+    json_reverse_iterator operator++(int)& // NOLINT(cert-dcl21-cpp)
     {
         return static_cast<json_reverse_iterator>(base_iterator::operator++(1));
     }
@@ -60,7 +60,7 @@ class json_reverse_iterator : public std::reverse_iterator<Base>
     }
 
     /// post-decrement (it--)
-    json_reverse_iterator const operator--(int) // NOLINT(readability-const-return-type)
+    json_reverse_iterator operator--(int)& // NOLINT(cert-dcl21-cpp)
     {
         return static_cast<json_reverse_iterator>(base_iterator::operator--(1));
     }
diff --git a/include/nlohmann/detail/iterators/primitive_iterator.hpp b/include/nlohmann/detail/iterators/primitive_iterator.hpp
index 15aa2f08aa..03bc37e2c7 100644
--- a/include/nlohmann/detail/iterators/primitive_iterator.hpp
+++ b/include/nlohmann/detail/iterators/primitive_iterator.hpp
@@ -87,7 +87,7 @@ class primitive_iterator_t
         return *this;
     }
 
-    primitive_iterator_t const operator++(int) noexcept // NOLINT(readability-const-return-type)
+    primitive_iterator_t operator++(int)& noexcept // NOLINT(cert-dcl21-cpp)
     {
         auto result = *this;
         ++m_it;
@@ -100,7 +100,7 @@ class primitive_iterator_t
         return *this;
     }
 
-    primitive_iterator_t const operator--(int) noexcept // NOLINT(readability-const-return-type)
+    primitive_iterator_t operator--(int)& noexcept // NOLINT(cert-dcl21-cpp)
     {
         auto result = *this;
         --m_it;
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 48999920dd..05000fbba4 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -11308,7 +11308,7 @@ class primitive_iterator_t
         return *this;
     }
 
-    primitive_iterator_t const operator++(int) noexcept // NOLINT(readability-const-return-type)
+    primitive_iterator_t operator++(int)& noexcept // NOLINT(cert-dcl21-cpp)
     {
         auto result = *this;
         ++m_it;
@@ -11321,7 +11321,7 @@ class primitive_iterator_t
         return *this;
     }
 
-    primitive_iterator_t const operator--(int) noexcept // NOLINT(readability-const-return-type)
+    primitive_iterator_t operator--(int)& noexcept // NOLINT(cert-dcl21-cpp)
     {
         auto result = *this;
         --m_it;
@@ -11728,7 +11728,7 @@ class iter_impl // NOLINT(cppcoreguidelines-special-member-functions,hicpp-speci
     @brief post-increment (it++)
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    iter_impl const operator++(int) // NOLINT(readability-const-return-type)
+    iter_impl operator++(int)& // NOLINT(cert-dcl21-cpp)
     {
         auto result = *this;
         ++(*this);
@@ -11779,7 +11779,7 @@ class iter_impl // NOLINT(cppcoreguidelines-special-member-functions,hicpp-speci
     @brief post-decrement (it--)
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    iter_impl const operator--(int) // NOLINT(readability-const-return-type)
+    iter_impl operator--(int)& // NOLINT(cert-dcl21-cpp)
     {
         auto result = *this;
         --(*this);
@@ -12167,7 +12167,7 @@ class json_reverse_iterator : public std::reverse_iterator<Base>
     explicit json_reverse_iterator(const base_iterator& it) noexcept : base_iterator(it) {}
 
     /// post-increment (it++)
-    json_reverse_iterator const operator++(int) // NOLINT(readability-const-return-type)
+    json_reverse_iterator operator++(int)& // NOLINT(cert-dcl21-cpp)
     {
         return static_cast<json_reverse_iterator>(base_iterator::operator++(1));
     }
@@ -12179,7 +12179,7 @@ class json_reverse_iterator : public std::reverse_iterator<Base>
     }
 
     /// post-decrement (it--)
-    json_reverse_iterator const operator--(int) // NOLINT(readability-const-return-type)
+    json_reverse_iterator operator--(int)& // NOLINT(cert-dcl21-cpp)
     {
         return static_cast<json_reverse_iterator>(base_iterator::operator--(1));
     }
diff --git a/test/src/unit-class_iterator.cpp b/test/src/unit-class_iterator.cpp
index 0e159fc381..e3a972f97c 100644
--- a/test/src/unit-class_iterator.cpp
+++ b/test/src/unit-class_iterator.cpp
@@ -33,6 +33,12 @@ SOFTWARE.
 #include <nlohmann/json.hpp>
 using nlohmann::json;
 
+template<typename Iter>
+using can_post_increment_temporary = decltype((std::declval<Iter>()++)++);
+
+template<typename Iter>
+using can_post_decrement_temporary = decltype((std::declval<Iter>()--)--);
+
 TEST_CASE("iterator class")
 {
     SECTION("construction")
@@ -399,4 +405,89 @@ TEST_CASE("iterator class")
             }
         }
     }
+    SECTION("equality-preserving")
+    {
+        SECTION("post-increment")
+        {
+            SECTION("primitive_iterator_t")
+            {
+                using Iter = nlohmann::detail::primitive_iterator_t;
+                CHECK(std::is_same < decltype(std::declval<Iter&>()++), Iter >::value);
+            }
+            SECTION("iter_impl")
+            {
+                using Iter = nlohmann::detail::iter_impl<json>;
+                CHECK(std::is_same < decltype(std::declval<Iter&>()++), Iter >::value);
+            }
+            SECTION("json_reverse_iterator")
+            {
+                using Base = nlohmann::detail::iter_impl<json>;
+                using Iter = nlohmann::detail::json_reverse_iterator<Base>;
+                CHECK(std::is_same < decltype(std::declval<Iter&>()++), Iter >::value);
+            }
+        }
+        SECTION("post-decrement")
+        {
+            SECTION("primitive_iterator_t")
+            {
+                using Iter = nlohmann::detail::primitive_iterator_t;
+                CHECK(std::is_same < decltype(std::declval<Iter&>()--), Iter >::value);
+            }
+            SECTION("iter_impl")
+            {
+                using Iter = nlohmann::detail::iter_impl<json>;
+                CHECK(std::is_same < decltype(std::declval<Iter&>()--), Iter >::value );
+            }
+            SECTION("json_reverse_iterator")
+            {
+                using Base = nlohmann::detail::iter_impl<json>;
+                using Iter = nlohmann::detail::json_reverse_iterator<Base>;
+                CHECK(std::is_same < decltype(std::declval<Iter&>()--), Iter >::value );
+            }
+        }
+    }
+    // prevent "accidental mutation of a temporary object"
+    SECTION("cert-dcl21-cpp")
+    {
+        using nlohmann::detail::is_detected;
+        SECTION("post-increment")
+        {
+            SECTION("primitive_iterator_t")
+            {
+                using Iter = nlohmann::detail::primitive_iterator_t;
+                CHECK_FALSE(is_detected<can_post_increment_temporary, Iter&>::value);
+            }
+            SECTION("iter_impl")
+            {
+                using Iter = nlohmann::detail::iter_impl<json>;
+                CHECK_FALSE(is_detected<can_post_increment_temporary, Iter&>::value);
+            }
+            SECTION("json_reverse_iterator")
+            {
+                using Base = nlohmann::detail::iter_impl<json>;
+                using Iter = nlohmann::detail::json_reverse_iterator<Base>;
+                CHECK_FALSE(is_detected<can_post_increment_temporary, Iter&>::value);
+            }
+        }
+        SECTION("post-decrement")
+        {
+            SECTION("primitive_iterator_t")
+            {
+                using Iter = nlohmann::detail::primitive_iterator_t;
+                CHECK_FALSE(is_detected<can_post_decrement_temporary, Iter&>::value);
+            }
+            SECTION("iter_impl")
+            {
+                using Iter = nlohmann::detail::iter_impl<json>;
+                CHECK_FALSE(is_detected<can_post_decrement_temporary, Iter&>::value);
+            }
+            SECTION("json_reverse_iterator")
+            {
+                using Base = nlohmann::detail::iter_impl<json>;
+                using Iter = nlohmann::detail::json_reverse_iterator<Base>;
+                CHECK_FALSE(is_detected<can_post_decrement_temporary, Iter&>::value);
+            }
+
+        }
+    }
 }