diff --git a/boost/network/protocol/http/client/options.hpp b/boost/network/protocol/http/client/options.hpp
index afc265abd..124ca27e1 100644
--- a/boost/network/protocol/http/client/options.hpp
+++ b/boost/network/protocol/http/client/options.hpp
@@ -94,39 +94,39 @@ class client_options {
   /// Set the filename of the certificate to load for the SSL connection for
   /// verification.
   client_options& openssl_certificate(string_type const& v) {
-    openssl_certificate_ = make_optional(v);
+    openssl_certificate_ = boost::make_optional(v);
     return *this;
   }
 
   /// Set the directory for which the certificate authority files are located.
   client_options& openssl_verify_path(string_type const& v) {
-    openssl_verify_path_ = make_optional(v);
+    openssl_verify_path_ = boost::make_optional(v);
     return *this;
   }
 
   /// Set the filename of the certificate to use for client-side SSL session
   /// establishment.
   client_options& openssl_certificate_file(string_type const& v) {
-    openssl_certificate_file_ = make_optional(v);
+    openssl_certificate_file_ = boost::make_optional(v);
     return *this;
   }
 
   /// Set the filename of the private key to use for client-side SSL session
   /// establishment.
   client_options& openssl_private_key_file(string_type const& v) {
-    openssl_private_key_file_ = make_optional(v);
+    openssl_private_key_file_ = boost::make_optional(v);
     return *this;
   }
 
   /// Set the ciphers to support for SSL negotiation.
   client_options& openssl_ciphers(string_type const& v) {
-    openssl_ciphers_ = make_optional(v);
+    openssl_ciphers_ = boost::make_optional(v);
     return *this;
   }
 
   /// Set the hostname for SSL SNI hostname support.
   client_options& openssl_sni_hostname(string_type const& v) {
-    openssl_sni_hostname_ = make_optional(v);
+    openssl_sni_hostname_ = boost::make_optional(v);
     return *this;
   }
 
diff --git a/boost/network/protocol/http/message/async_message.hpp b/boost/network/protocol/http/message/async_message.hpp
index 8fd86a0a0..ddce8a235 100644
--- a/boost/network/protocol/http/message/async_message.hpp
+++ b/boost/network/protocol/http/message/async_message.hpp
@@ -97,7 +97,7 @@ struct async_message {
     for (string_type const & key : removed_headers) {
       raw_headers.erase(key);
     }
-    retrieved_headers_ = make_optional(raw_headers);
+    retrieved_headers_ = boost::make_optional(raw_headers);
     return *retrieved_headers_;
   }