try boost 1.65

Change-Id: I425bab159a778455fb4bcc6144274c2c068f42de
diff --git a/.travis.yml b/.travis.yml
index 15e5888..eb01d8d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,7 @@
 version: ~> 1.0
 language: cpp
 os: linux
-dist: focal
+dist: bionic
 
 arch:
   - amd64
diff --git a/tools/ndncert-ca-server.cpp b/tools/ndncert-ca-server.cpp
index c633c83..8acd13b 100644
--- a/tools/ndncert-ca-server.cpp
+++ b/tools/ndncert-ca-server.cpp
@@ -39,7 +39,11 @@
 static bool
 writeDataToRepo(const Data& data) {
   boost::asio::ip::tcp::iostream requestStream;
-  requestStream.expires_after(std::chrono::seconds(3));
+#if BOOST_VERSION >= 106600
+    requestStream.expires_after(std::chrono::seconds(3));
+#else
+    requestStream.expires_at(std::chrono::seconds(3));
+#endif
   requestStream.connect(repoHost, repoPort);
   if (!requestStream) {
     std::cerr << "ERROR: Cannot publish certificate to repo-ng"