build: require boost >= 1.71.0

Refs: #5276
Change-Id: I287a52dab0212d1ce0da77afb563554214cac68a
diff --git a/tests/unit-tests/dummy-forwarder.cpp b/tests/unit-tests/dummy-forwarder.cpp
index 2bcc3bc..ca43032 100644
--- a/tests/unit-tests/dummy-forwarder.cpp
+++ b/tests/unit-tests/dummy-forwarder.cpp
@@ -19,12 +19,13 @@
 
 #include "dummy-forwarder.hpp"
 
-#include <boost/asio/io_service.hpp>
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/post.hpp>
 
 namespace ndn {
 namespace chronosync {
 
-DummyForwarder::DummyForwarder(boost::asio::io_service& io, KeyChain& keyChain)
+DummyForwarder::DummyForwarder(boost::asio::io_context& io, KeyChain& keyChain)
   : m_io(io)
   , m_keyChain(keyChain)
 {
@@ -42,7 +43,7 @@
         if (self == &*otherFace) {
           continue;
         }
-        m_io.post([=] { otherFace->receive(i); });
+        boost::asio::post(m_io, [=] { otherFace->receive(i); });
       }
     });
 
@@ -52,7 +53,7 @@
         if (self == &*otherFace) {
           continue;
         }
-        m_io.post([=] { otherFace->receive(d); });
+        boost::asio::post(m_io, [=] { otherFace->receive(d); });
       }
     });
 
@@ -62,7 +63,7 @@
         if (self == &*otherFace) {
           continue;
         }
-        m_io.post([=] { otherFace->receive(n); });
+        boost::asio::post(m_io, [=] { otherFace->receive(n); });
       }
     });
 
diff --git a/tests/unit-tests/dummy-forwarder.hpp b/tests/unit-tests/dummy-forwarder.hpp
index 60e6904..372186e 100644
--- a/tests/unit-tests/dummy-forwarder.hpp
+++ b/tests/unit-tests/dummy-forwarder.hpp
@@ -38,7 +38,7 @@
 class DummyForwarder
 {
 public:
-  DummyForwarder(boost::asio::io_service& io, KeyChain& keyChain);
+  DummyForwarder(boost::asio::io_context& io, KeyChain& keyChain);
 
   Face&
   addFace();
@@ -53,7 +53,7 @@
   removeFaces();
 
 private:
-  boost::asio::io_service& m_io;
+  boost::asio::io_context& m_io;
   KeyChain& m_keyChain;
   std::vector<std::shared_ptr<DummyClientFace>> m_faces;
 };
diff --git a/tests/unit-tests/test-logic.cpp b/tests/unit-tests/test-logic.cpp
index 1a1257a..3cd7f9d 100644
--- a/tests/unit-tests/test-logic.cpp
+++ b/tests/unit-tests/test-logic.cpp
@@ -363,7 +363,7 @@
   systemClock->advance(ndn::time::hours(1));
 
   BOOST_CHECK_EQUAL(io.poll(), 0); // no delayed handlers are expected
-  BOOST_CHECK_EQUAL(io.stopped(), true); // io_service expected to be stopped
+  BOOST_CHECK_EQUAL(io.stopped(), true); // io_context expected to be stopped
 }
 
 BOOST_FIXTURE_TEST_CASE(TrimState, ndn::tests::IdentityManagementTimeFixture)
diff --git a/tests/unit-tests/test-multiple-user.cpp b/tests/unit-tests/test-multiple-user.cpp
index b8a5dbd..83d00da 100644
--- a/tests/unit-tests/test-multiple-user.cpp
+++ b/tests/unit-tests/test-multiple-user.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
 /*
- * Copyright (c) 2012-2022 University of California, Los Angeles
+ * Copyright (c) 2012-2023 University of California, Los Angeles
  *
  * This file is part of ChronoSync, synchronization library for distributed realtime
  * applications for NDN.
@@ -72,7 +72,7 @@
   Name syncPrefix;
   Name userPrefix[3];
 
-  boost::asio::io_service io;
+  boost::asio::io_context io;
   shared_ptr<ndn::Face> face;
   ndn::Scheduler scheduler;
   shared_ptr<Handler> handler;