diff --git a/libcxx/include/__bit_reference b/libcxx/include/__bit_reference
--- a/libcxx/include/__bit_reference
+++ b/libcxx/include/__bit_reference
@@ -65,6 +65,16 @@
         return *this;
     }
 
+#if _LIBCPP_STD_VER > 20
+    _LIBCPP_HIDE_FROM_ABI const __bit_reference& operator=(bool __x) const noexcept {
+        if (__x)
+            *__seg_ |= __mask_;
+        else
+            *__seg_ &= ~__mask_;
+        return *this;
+    }
+#endif
+
     _LIBCPP_INLINE_VISIBILITY
     __bit_reference& operator=(const __bit_reference& __x) _NOEXCEPT
         {return operator=(static_cast<bool>(__x));}
diff --git a/libcxx/test/std/containers/sequences/vector.bool/iterator_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/iterator_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/sequences/vector.bool/iterator_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/iterator_concept_conformance.compile.pass.cpp
@@ -11,9 +11,10 @@
 
 // iterator, const_iterator, reverse_iterator, const_reverse_iterator
 
+#include <iterator>
 #include <vector>
 
-#include <iterator>
+#include "test_macros.h"
 
 using iterator = std::vector<bool>::iterator;
 using const_iterator = std::vector<bool>::const_iterator;
@@ -25,7 +26,11 @@
 static_assert( std::random_access_iterator<reverse_iterator>);
 static_assert(!std::contiguous_iterator<iterator>);
 static_assert(!std::contiguous_iterator<reverse_iterator>);
+#if TEST_STD_VER > 20
+static_assert( std::indirectly_writable<iterator, value_type>);
+#else
 static_assert(!std::indirectly_writable<iterator, value_type>);
+#endif
 static_assert( std::sentinel_for<iterator, iterator>);
 static_assert( std::sentinel_for<iterator, const_iterator>);
 static_assert(!std::sentinel_for<iterator, reverse_iterator>);
diff --git a/libcxx/test/std/containers/sequences/vector.bool/reference/assign_bool.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/reference/assign_bool.pass.cpp
--- a/libcxx/test/std/containers/sequences/vector.bool/reference/assign_bool.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/reference/assign_bool.pass.cpp
@@ -13,6 +13,8 @@
 #include <cassert>
 #include <vector>
 
+#include "test_macros.h"
+
 bool test() {
   std::vector<bool> vec;
   typedef std::vector<bool>::reference Ref;
@@ -31,6 +33,15 @@
 
   assert(cref);
 
+#if TEST_STD_VER > 20
+  cref = false;
+  assert(!vec[0]);
+  assert(!vec[1]);
+  cref = true;
+  assert(vec[0]);
+  assert(!vec[1]);
+#endif
+
   return true;
 }