diff --git a/doc/release_notes.html b/doc/release_notes.html
index 7510bad..964e165 100644
--- a/doc/release_notes.html
+++ b/doc/release_notes.html
@@ -72,6 +72,10 @@ Acknowledgements
     in accordance with standard specifications in <b>[swappable.requirements]</b>
     (<a href="https://github.com/boostorg/multi_index/issues/29">issue #29</a>).
   </li>
+ <li>Provided some internal copy constructors and assignment operators whose default
+    implicit definition is deprecated in C++11 onwards (<b>[depr.impldec]</b>), which
+    was warned about on some compilers. 
+ </li>
   <li>Maintenance work.</li>
 </ul>
 </p>
@@ -650,9 +654,9 @@ Acknowledgements
 
 <br>
 
-<p>Revised November 18th 2019</p>
+<p>Revised January 21st 2020</p>
 
-<p>&copy; Copyright 2003-2019 Joaqu&iacute;n M L&oacute;pez Mu&ntilde;oz.
+<p>&copy; Copyright 2003-2020 Joaqu&iacute;n M L&oacute;pez Mu&ntilde;oz.
 Distributed under the Boost Software 
 License, Version 1.0. (See accompanying file <a href="../../../LICENSE_1_0.txt">
 LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
diff --git a/include/boost/multi_index/detail/safe_mode.hpp b/include/boost/multi_index/detail/safe_mode.hpp
index 905270e..b2ed69f 100644
--- a/include/boost/multi_index/detail/safe_mode.hpp
+++ b/include/boost/multi_index/detail/safe_mode.hpp
@@ -1,4 +1,4 @@
-/* Copyright 2003-2013 Joaquin M Lopez Munoz.
+/* Copyright 2003-2020 Joaquin M Lopez Munoz.
  * Distributed under the Boost Software License, Version 1.0.
  * (See accompanying file LICENSE_1_0.txt or copy at
  * http://www.boost.org/LICENSE_1_0.txt)
@@ -430,6 +430,7 @@ public:
   safe_iterator(
     const T0& t0,const T1& t1,safe_container<container_type>* cont_):
     super(Iterator(t0,t1)),safe_super(cont_){}
+  safe_iterator(const safe_iterator& x):super(x),safe_super(x){}
 
   safe_iterator& operator=(const safe_iterator& x)
   {
diff --git a/test/non_std_allocator.hpp b/test/non_std_allocator.hpp
index 44a3499..80f366c 100644
--- a/test/non_std_allocator.hpp
+++ b/test/non_std_allocator.hpp
@@ -1,6 +1,6 @@
 /* Used in Boost.MultiIndex tests.
  *
- * Copyright 2003-2018 Joaquin M Lopez Munoz.
+ * Copyright 2003-2020 Joaquin M Lopez Munoz.
  * Distributed under the Boost Software License, Version 1.0.
  * (See accompanying file LICENSE_1_0.txt or copy at
  * http://www.boost.org/LICENSE_1_0.txt)
@@ -113,6 +113,7 @@ public:
   non_std_allocator(){}
   non_std_allocator(const non_std_allocator<T>&){}
   template<class U>non_std_allocator(const non_std_allocator<U>&,int=0){}
+  non_std_allocator& operator=(const non_std_allocator<T>&){return *this;}
 
   pointer allocate(size_type n)
   {
diff --git a/test/test_key_extractors.cpp b/test/test_key_extractors.cpp
index 95643df..31eec10 100644
--- a/test/test_key_extractors.cpp
+++ b/test/test_key_extractors.cpp
@@ -1,6 +1,6 @@
 /* Boost.MultiIndex test for key extractors.
  *
- * Copyright 2003-2019 Joaquin M Lopez Munoz.
+ * Copyright 2003-2020 Joaquin M Lopez Munoz.
  * Distributed under the Boost Software License, Version 1.0.
  * (See accompanying file LICENSE_1_0.txt or copy at
  * http://www.boost.org/LICENSE_1_0.txt)
@@ -46,6 +46,8 @@ struct test_class
 
   test_class(int i=0):int_member(i),int_cmember(i){}
   test_class(int i,int j):int_member(i),int_cmember(j){}
+  test_class(const test_class& x):
+    int_member(x.int_member),int_cmember(x.int_cmember){}
 
   test_class& operator=(const test_class& x)
   {