diff --git a/include/boost/smart_ptr/detail/sp_counted_base_acc_ia64.hpp b/include/boost/smart_ptr/detail/sp_counted_base_acc_ia64.hpp
index b31997d..8482515 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_acc_ia64.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_acc_ia64.hpp
@@ -16,6 +16,7 @@
 //
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 #include <machine/sys/inline.h>
 
@@ -26,6 +27,8 @@ BOOST_PRAGMA_MESSAGE("Using HP aCC++/HP-UX/IA64 sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 namespace boost
 {
 
diff --git a/include/boost/smart_ptr/detail/sp_counted_base_cw_ppc.hpp b/include/boost/smart_ptr/detail/sp_counted_base_cw_ppc.hpp
index f9df68a..81387ce 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_cw_ppc.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_cw_ppc.hpp
@@ -25,6 +25,7 @@
 //
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 
 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
@@ -34,6 +35,8 @@ BOOST_PRAGMA_MESSAGE("Using CodeWarrior/PowerPC sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 namespace boost
 {
 
diff --git a/include/boost/smart_ptr/detail/sp_counted_base_gcc_ia64.hpp b/include/boost/smart_ptr/detail/sp_counted_base_gcc_ia64.hpp
index 0c8d172..a6492ec 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_gcc_ia64.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_gcc_ia64.hpp
@@ -17,6 +17,7 @@
 //
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 
 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
@@ -26,6 +27,8 @@ BOOST_PRAGMA_MESSAGE("Using g++/IA64 sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 namespace boost
 {
 
diff --git a/include/boost/smart_ptr/detail/sp_counted_base_gcc_mips.hpp b/include/boost/smart_ptr/detail/sp_counted_base_gcc_mips.hpp
index 5cc5de9..3d3c7d3 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_gcc_mips.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_gcc_mips.hpp
@@ -21,6 +21,7 @@
 //
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 
 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
@@ -30,6 +31,8 @@ BOOST_PRAGMA_MESSAGE("Using g++/MIPS sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 namespace boost
 {
 
diff --git a/include/boost/smart_ptr/detail/sp_counted_base_gcc_ppc.hpp b/include/boost/smart_ptr/detail/sp_counted_base_gcc_ppc.hpp
index c5f84f5..12c8774 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_gcc_ppc.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_gcc_ppc.hpp
@@ -25,6 +25,7 @@
 //
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 
 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
@@ -34,6 +35,8 @@ BOOST_PRAGMA_MESSAGE("Using g++/PowerPC sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 namespace boost
 {
 
diff --git a/include/boost/smart_ptr/detail/sp_counted_base_gcc_sparc.hpp b/include/boost/smart_ptr/detail/sp_counted_base_gcc_sparc.hpp
index 8062487..a30e2a7 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_gcc_sparc.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_gcc_sparc.hpp
@@ -20,6 +20,7 @@
 //  Thanks to Michael van der Westhuizen
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 #include <inttypes.h> // int32_t
 
@@ -30,6 +31,8 @@ BOOST_PRAGMA_MESSAGE("Using g++/Sparc sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 namespace boost
 {
 
diff --git a/include/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp b/include/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp
index 1c55918..420265d 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp
@@ -25,6 +25,7 @@
 //
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 
 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
@@ -34,6 +35,8 @@ BOOST_PRAGMA_MESSAGE("Using g++/x86 sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 namespace boost
 {
 
diff --git a/include/boost/smart_ptr/detail/sp_counted_base_snc_ps3.hpp b/include/boost/smart_ptr/detail/sp_counted_base_snc_ps3.hpp
index d60dd75..fc84ec1 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_snc_ps3.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_snc_ps3.hpp
@@ -20,6 +20,7 @@
 //  Thanks to Michael van der Westhuizen
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 #include <inttypes.h> // uint32_t
 
@@ -30,6 +31,8 @@ BOOST_PRAGMA_MESSAGE("Using PS3 sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 namespace boost
 {
 
diff --git a/include/boost/smart_ptr/detail/sp_counted_base_vacpp_ppc.hpp b/include/boost/smart_ptr/detail/sp_counted_base_vacpp_ppc.hpp
index e08536d..d3e5442 100644
--- a/include/boost/smart_ptr/detail/sp_counted_base_vacpp_ppc.hpp
+++ b/include/boost/smart_ptr/detail/sp_counted_base_vacpp_ppc.hpp
@@ -22,6 +22,7 @@
 //
 
 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
+#include <boost/smart_ptr/detail/sp_obsolete.hpp>
 #include <boost/config.hpp>
 
 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
@@ -31,6 +32,8 @@ BOOST_PRAGMA_MESSAGE("Using xlC/PowerPC sp_counted_base")
 
 #endif
 
+BOOST_SP_OBSOLETE()
+
 extern "builtin" void __lwsync(void);
 extern "builtin" void __isync(void);
 extern "builtin" int __fetch_and_add(volatile int* addr, int val);
diff --git a/include/boost/smart_ptr/detail/sp_obsolete.hpp b/include/boost/smart_ptr/detail/sp_obsolete.hpp
new file mode 100644
index 0000000..021e72e
--- /dev/null
+++ b/include/boost/smart_ptr/detail/sp_obsolete.hpp
@@ -0,0 +1,32 @@
+#ifndef BOOST_SMART_PTR_DETAIL_SP_OBSOLETE_HPP_INCLUDED
+#define BOOST_SMART_PTR_DETAIL_SP_OBSOLETE_HPP_INCLUDED
+
+// MS compatible compilers support #pragma once
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
+#endif
+
+
+// boost/smart_ptr/detail/sp_obsolete.hpp
+//
+// Copyright 2020 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+//
+// Defines the BOOST_SP_OBSOLETE macro that emits a deprecation
+// message.
+
+#include <boost/config/pragma_message.hpp>
+
+#if !defined( BOOST_SP_NO_OBSOLETE_MESSAGE )
+
+#define BOOST_SP_OBSOLETE() BOOST_PRAGMA_MESSAGE("This platform-specific implementation is presumed obsolete and is slated for removal. If you want it retained, please open an issue in https://github.com/boostorg/smart_ptr.")
+
+#else
+
+#define BOOST_SP_OBSOLETE()
+
+#endif
+
+#endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_OBSOLETE_HPP_INCLUDED