diff --git a/NEWS b/NEWS
index 25359c62..92ce72e7 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,11 @@
 0MQ version 4.3.x stable, released on 20xx/xx/xx
 ================================================
 
+* Note for packagers: an external, self-contained sha1 library is now
+  included in the source tree under external/sha1/ - it is licensed
+  under BSD-3-Clause and thus it is fully compatible with libzmq's
+  license.
+
 0MQ version 4.3.2 stable, released on 2019/07/08
 ================================================
 
diff --git a/external/sha1/license.txt b/external/sha1/license.txt
new file mode 100644
index 00000000..3b5eb95a
--- /dev/null
+++ b/external/sha1/license.txt
@@ -0,0 +1,26 @@
+Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+3. Neither the name of the project nor the names of its contributors
+       may be used to endorse or promote products derived from this software
+       without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED.      IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.
diff --git a/src/stdint.hpp b/src/stdint.hpp
index dc4d5df1..e04e7fc2 100644
--- a/src/stdint.hpp
+++ b/src/stdint.hpp
@@ -69,6 +69,8 @@ typedef unsigned __int64 uint64_t;
 
 #else
 
+//  To define SIZE_MAX with older compilers
+#define __STDC_LIMIT_MACROS
 #include <stdint.h>
 
 #endif
diff --git a/src/ws_connecter.cpp b/src/ws_connecter.cpp
index 10091f27..deefaefa 100644
--- a/src/ws_connecter.cpp
+++ b/src/ws_connecter.cpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_connecter.hpp b/src/ws_connecter.hpp
index eb67b0de..2faa3a6a 100644
--- a/src/ws_connecter.hpp
+++ b/src/ws_connecter.hpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_decoder.cpp b/src/ws_decoder.cpp
index 0489af58..a87bdd48 100644
--- a/src/ws_decoder.cpp
+++ b/src/ws_decoder.cpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_decoder.hpp b/src/ws_decoder.hpp
index 6a5f0a6a..16330411 100644
--- a/src/ws_decoder.hpp
+++ b/src/ws_decoder.hpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_encoder.cpp b/src/ws_encoder.cpp
index c1b24cb5..8744fbae 100644
--- a/src/ws_encoder.cpp
+++ b/src/ws_encoder.cpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_encoder.hpp b/src/ws_encoder.hpp
index d8dad36c..37c7775e 100644
--- a/src/ws_encoder.hpp
+++ b/src/ws_encoder.hpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_engine.cpp b/src/ws_engine.cpp
index 552b3be0..5448472c 100644
--- a/src/ws_engine.cpp
+++ b/src/ws_engine.cpp
@@ -1,5 +1,5 @@
 /*
-Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
 This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_engine.hpp b/src/ws_engine.hpp
index d3527843..f9804f9d 100644
--- a/src/ws_engine.hpp
+++ b/src/ws_engine.hpp
@@ -1,3 +1,31 @@
+/*
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
+
+    This file is part of libzmq, the ZeroMQ core engine in C++.
+
+    libzmq is free software; you can redistribute it and/or modify it under
+    the terms of the GNU Lesser General Public License (LGPL) as published
+    by the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    As a special exception, the Contributors give you permission to link
+    this library with independent modules to produce an executable,
+    regardless of the license terms of these independent modules, and to
+    copy and distribute the resulting executable under terms of your choice,
+    provided that you also meet, for each linked independent module, the
+    terms and conditions of the license of that module. An independent
+    module is a module which is not derived from or based on this library.
+    If you modify this library, you must extend this exception to your
+    version of the library.
+
+    libzmq is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
 
 #ifndef __ZMQ_WS_ENGINE_HPP_INCLUDED__
 #define __ZMQ_WS_ENGINE_HPP_INCLUDED__
diff --git a/src/ws_listener.cpp b/src/ws_listener.cpp
index 6d3b49f4..e261752b 100644
--- a/src/ws_listener.cpp
+++ b/src/ws_listener.cpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_listener.hpp b/src/ws_listener.hpp
index 47a3f744..faa42f14 100644
--- a/src/ws_listener.hpp
+++ b/src/ws_listener.hpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.
 
diff --git a/src/ws_protocol.hpp b/src/ws_protocol.hpp
index 5642aa07..b4b7e81f 100644
--- a/src/ws_protocol.hpp
+++ b/src/ws_protocol.hpp
@@ -1,5 +1,5 @@
 /*
-    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
+    Copyright (c) 2007-2019 Contributors as noted in the AUTHORS file
 
     This file is part of libzmq, the ZeroMQ core engine in C++.