Index: gazebo-11.15.1/gazebo/transport/Connection.cc
===================================================================
--- gazebo-11.15.1.orig/gazebo/transport/Connection.cc
+++ gazebo-11.15.1/gazebo/transport/Connection.cc
@@ -73,7 +73,7 @@ IOManager *Connection::iomanager = NULL;
 // is stolen from adress::is_unspecified function in boost v1.52.
 static bool addressIsUnspecified(const boost::asio::ip::address_v4 &_addr)
 {
-  return _addr.to_ulong() == 0;
+  return _addr.to_uint() == 0;
 }
 
 // Version 1.52 of boost has an address::is_loopback function, but
@@ -81,7 +81,7 @@ static bool addressIsUnspecified(const b
 // is stolen from adress::is_loopback function in boost v1.52.
 static bool addressIsLoopback(const boost::asio::ip::address_v4 &_addr)
 {
-  return (_addr.to_ulong() & 0xFF000000) == 0x7F000000;
+  return (_addr.to_uint() & 0xFF000000) == 0x7F000000;
 }
 
 //////////////////////////////////////////////////
@@ -151,15 +151,15 @@ bool Connection::Connect(const std::stri
     host = _host.substr(7, _host.size() - 7);
 
   // Resolve the host name into an IP address
-  boost::asio::ip::tcp::resolver::iterator end;
   boost::asio::ip::tcp::resolver resolver(iomanager->GetIO());
-  boost::asio::ip::tcp::resolver::query query(host, service,
+
+  auto res = resolver.resolve(host, service,
       boost::asio::ip::resolver_query_base::numeric_service);
-  boost::asio::ip::tcp::resolver::iterator endpointIter;
+  auto endpointIter = res.begin();
+  auto end = res.end();
 
   try
   {
-    endpointIter = resolver.resolve(query);
 
     // Find the first valid IPv4 address
     for (; endpointIter != end &&
@@ -690,9 +690,9 @@ boost::asio::ip::tcp::endpoint Connectio
   if (hostname && !std::string(hostname).empty())
   {
     boost::asio::ip::tcp::resolver resolver(iomanager->GetIO());
-    boost::asio::ip::tcp::resolver::query query(hostname, "");
-    boost::asio::ip::tcp::resolver::iterator iter = resolver.resolve(query);
-    boost::asio::ip::tcp::resolver::iterator end;
+    auto res = resolver.resolve(hostname, "");
+    auto iter = res.begin();
+    auto end = res.end();
 
     // Loop through the results, and stop at the first valid address.
     while (iter != end)
@@ -724,7 +724,7 @@ boost::asio::ip::tcp::endpoint Connectio
             << "] is invalid. We will still try to use it, be warned.\n";
     }
 
-    address = boost::asio::ip::address_v4::from_string(ip);
+    address = boost::asio::ip::make_address_v4(ip);
   }
 
   // Try to automatically find a valid address if GAZEBO_IP and
@@ -774,7 +774,7 @@ boost::asio::ip::tcp::endpoint Connectio
         if (!ValidateIP(host))
           continue;
 
-        address = boost::asio::ip::address_v4::from_string(host);
+        address = boost::asio::ip::make_address_v4(host);
 
         // Also make sure that the IP address is not a loopback interface.
         if (!addressIsLoopback(address))
@@ -868,7 +868,7 @@ boost::asio::ip::tcp::endpoint Connectio
       "but will almost certainly not work if you have remote processes."
       "Report to the disc-zmq development team to seek a fix." << std::endl;
   }
-  address = boost::asio::ip::address_v4::from_string(retAddr);
+  address = boost::asio::ip::make_address_v4(retAddr);
 #endif
   }
 
@@ -923,8 +923,9 @@ std::string Connection::GetHostname(boos
   else
   {
     boost::asio::ip::tcp::resolver resolver(iomanager->GetIO());
-    boost::asio::ip::tcp::resolver::iterator iter = resolver.resolve(_ep);
-    boost::asio::ip::tcp::resolver::iterator end;
+    auto res = resolver.resolve(_ep);
+    auto iter = res.begin();
+    auto end = res.end();
 
     while (iter != end)
     {
@@ -950,7 +951,7 @@ std::string Connection::GetLocalHostname
 
 //////////////////////////////////////////////////
 void Connection::OnConnect(const boost::system::error_code &_error,
-    boost::asio::ip::tcp::resolver::iterator /*_endPointIter*/)
+    boost::asio::ip::tcp::resolver::results_type::iterator /*_endPointIter*/)
 {
   // This function is called when a connection is successfully (or
   // unsuccessfully) established.
Index: gazebo-11.15.1/gazebo/transport/Connection.hh
===================================================================
--- gazebo-11.15.1.orig/gazebo/transport/Connection.hh
+++ gazebo-11.15.1/gazebo/transport/Connection.hh
@@ -409,7 +409,7 @@ namespace gazebo
       /// \param[in] _error Error code thrown during connection
       /// \param[in] _endPointIter Pointer to resolver iterator
       private: void OnConnect(const boost::system::error_code &_error,
-                  boost::asio::ip::tcp::resolver::iterator _endPointIter);
+                  boost::asio::ip::tcp::resolver::results_type::iterator _endPointIter);
 
       /// \brief Socket pointer
       private: boost::asio::ip::tcp::socket *socket;
Index: gazebo-11.15.1/gazebo/transport/IOManager.cc
===================================================================
--- gazebo-11.15.1.orig/gazebo/transport/IOManager.cc
+++ gazebo-11.15.1/gazebo/transport/IOManager.cc
@@ -17,6 +17,7 @@
 #include <atomic>
 #include <boost/bind/bind.hpp>
 #include <boost/thread/thread.hpp>
+#include <boost/asio/executor_work_guard.hpp>
 #include <iostream>
 #include "gazebo/transport/IOManager.hh"
 
@@ -28,10 +29,10 @@ namespace transport
 class IOManagerPrivate
 {
   /// \brief IO service.
-  public: boost::asio::io_service *io_service = nullptr;
+  public: boost::asio::io_context *io_service = nullptr;
 
   /// \brief Use io_service::work to keep the io_service running in thread.
-  public: boost::asio::io_service::work *work = nullptr;
+  //public: boost::asio::executor_work_guard<boost::asio::io_context> work;
 
   /// \brief Reference count of connections using this IOManager.
   public: std::atomic_int count;
@@ -44,12 +45,11 @@ class IOManagerPrivate
 IOManager::IOManager()
   : dataPtr(new IOManagerPrivate)
 {
-  this->dataPtr->io_service = new boost::asio::io_service;
-  this->dataPtr->work = new boost::asio::io_service::work(
-      *this->dataPtr->io_service);
+  this->dataPtr->io_service = new boost::asio::io_context;
+  //this->dataPtr->work = boost::asio::make_work_guard(*this->dataPtr->io_service);
   this->dataPtr->count = 0;
   this->dataPtr->thread = new boost::thread(boost::bind(
-      &boost::asio::io_service::run, this->dataPtr->io_service));
+      &boost::asio::io_context::run, this->dataPtr->io_service));
 }
 
 /////////////////////////////////////////////////
@@ -57,9 +57,6 @@ IOManager::~IOManager()
 {
   this->Stop();
 
-  delete this->dataPtr->work;
-  this->dataPtr->work = nullptr;
-
   delete this->dataPtr->io_service;
   this->dataPtr->io_service = nullptr;
 
@@ -70,7 +67,7 @@ IOManager::~IOManager()
 /////////////////////////////////////////////////
 void IOManager::Stop()
 {
-  this->dataPtr->io_service->reset();
+  this->dataPtr->io_service->restart();
   this->dataPtr->io_service->stop();
   if (this->dataPtr->thread)
   {
@@ -81,7 +78,7 @@ void IOManager::Stop()
 }
 
 /////////////////////////////////////////////////
-boost::asio::io_service &IOManager::GetIO()
+boost::asio::io_context &IOManager::GetIO()
 {
   return *this->dataPtr->io_service;
 }
Index: gazebo-11.15.1/gazebo/transport/IOManager.hh
===================================================================
--- gazebo-11.15.1.orig/gazebo/transport/IOManager.hh
+++ gazebo-11.15.1/gazebo/transport/IOManager.hh
@@ -42,7 +42,7 @@ namespace gazebo
 
       /// \brief Get handle to boost::asio IO service
       /// \return Handle to boost::asio IO service
-      public: boost::asio::io_service &GetIO();
+      public: boost::asio::io_context &GetIO();
 
       /// \brief Increment the event count by 1
       public: void IncCount();