diff --git a/tests/time_test.cpp b/tests/time_test.cpp
index 4ac93f2..dee272d 100644
--- a/tests/time_test.cpp
+++ b/tests/time_test.cpp
@@ -37,6 +37,7 @@ BOOST_AUTO_TEST_CASE(time_point_sec_test)
     BOOST_CHECK_EQUAL( "20380119T031408", tp2g.to_non_delimited_iso_string() );
 
     time_point_sec tp3g(0xc0000000U);
+    // commented next 2 tests as they will only work with boost >= 1.64
     //BOOST_CHECK_EQUAL( "2072-01-28T16:51:12", tp3g.to_iso_string() );
     //BOOST_CHECK_EQUAL( "20720128T165112", tp3g.to_non_delimited_iso_string() );