diff --git a/libcxx/include/__availability b/libcxx/include/__availability
--- a/libcxx/include/__availability
+++ b/libcxx/include/__availability
@@ -215,13 +215,20 @@
 #   define _LIBCPP_AVAILABILITY_TO_CHARS                                        \
         _LIBCPP_AVAILABILITY_FILESYSTEM
 
-    // Note: Those are not ABI-stable yet, so we can't ship them.
 #   define _LIBCPP_AVAILABILITY_SYNC                                            \
-        __attribute__((unavailable))
-#   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_atomic_wait
-#   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_barrier
-#   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_latch
-#   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore
+        __attribute__((availability(macosx,strict,introduced=11.0)))            \
+        __attribute__((availability(ios,strict,introduced=14.0)))               \
+        __attribute__((availability(tvos,strict,introduced=14.0)))              \
+        __attribute__((availability(watchos,strict,introduced=7.0)))
+#   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 110000) ||    \
+        (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 140000) || \
+        (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 140000) ||         \
+        (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 70000)
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_atomic_wait
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_barrier
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_latch
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore
+#   endif
 
 #else
 
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.wait/atomic_wait.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.wait/atomic_wait.pass.cpp
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.wait/atomic_wait.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.wait/atomic_wait.pass.cpp
@@ -10,9 +10,8 @@
 // XFAIL: c++03
 // XFAIL: !non-lockfree-atomics
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.barrier/arrive.pass.cpp b/libcxx/test/std/thread/thread.barrier/arrive.pass.cpp
--- a/libcxx/test/std/thread/thread.barrier/arrive.pass.cpp
+++ b/libcxx/test/std/thread/thread.barrier/arrive.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.barrier/arrive_and_drop.pass.cpp b/libcxx/test/std/thread/thread.barrier/arrive_and_drop.pass.cpp
--- a/libcxx/test/std/thread/thread.barrier/arrive_and_drop.pass.cpp
+++ b/libcxx/test/std/thread/thread.barrier/arrive_and_drop.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.barrier/arrive_and_wait.pass.cpp b/libcxx/test/std/thread/thread.barrier/arrive_and_wait.pass.cpp
--- a/libcxx/test/std/thread/thread.barrier/arrive_and_wait.pass.cpp
+++ b/libcxx/test/std/thread/thread.barrier/arrive_and_wait.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.barrier/completion.pass.cpp b/libcxx/test/std/thread/thread.barrier/completion.pass.cpp
--- a/libcxx/test/std/thread/thread.barrier/completion.pass.cpp
+++ b/libcxx/test/std/thread/thread.barrier/completion.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.latch/arrive_and_wait.pass.cpp b/libcxx/test/std/thread/thread.latch/arrive_and_wait.pass.cpp
--- a/libcxx/test/std/thread/thread.latch/arrive_and_wait.pass.cpp
+++ b/libcxx/test/std/thread/thread.latch/arrive_and_wait.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.latch/count_down.pass.cpp b/libcxx/test/std/thread/thread.latch/count_down.pass.cpp
--- a/libcxx/test/std/thread/thread.latch/count_down.pass.cpp
+++ b/libcxx/test/std/thread/thread.latch/count_down.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.latch/try_wait.pass.cpp b/libcxx/test/std/thread/thread.latch/try_wait.pass.cpp
--- a/libcxx/test/std/thread/thread.latch/try_wait.pass.cpp
+++ b/libcxx/test/std/thread/thread.latch/try_wait.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.semaphore/acquire.pass.cpp b/libcxx/test/std/thread/thread.semaphore/acquire.pass.cpp
--- a/libcxx/test/std/thread/thread.semaphore/acquire.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/acquire.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.semaphore/binary.pass.cpp b/libcxx/test/std/thread/thread.semaphore/binary.pass.cpp
--- a/libcxx/test/std/thread/thread.semaphore/binary.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/binary.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.semaphore/release.pass.cpp b/libcxx/test/std/thread/thread.semaphore/release.pass.cpp
--- a/libcxx/test/std/thread/thread.semaphore/release.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/release.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.semaphore/timed.pass.cpp b/libcxx/test/std/thread/thread.semaphore/timed.pass.cpp
--- a/libcxx/test/std/thread/thread.semaphore/timed.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/timed.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13
diff --git a/libcxx/test/std/thread/thread.semaphore/try_acquire.pass.cpp b/libcxx/test/std/thread/thread.semaphore/try_acquire.pass.cpp
--- a/libcxx/test/std/thread/thread.semaphore/try_acquire.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/try_acquire.pass.cpp
@@ -9,9 +9,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
-// This test requires the dylib support introduced in D68480,
-// which hasn't shipped yet.
-// XFAIL: with_system_cxx_lib=macosx
+// This test requires the dylib support introduced in D68480, which shipped in
+// macOS 11.0.
 // XFAIL: with_system_cxx_lib=macosx10.15
 // XFAIL: with_system_cxx_lib=macosx10.14
 // XFAIL: with_system_cxx_lib=macosx10.13