diff --git a/tests/test-case.t.cpp.sample b/tests/test-case.t.cpp.sample
index bfff444..bfc8219 100644
--- a/tests/test-case.t.cpp.sample
+++ b/tests/test-case.t.cpp.sample
@@ -42,7 +42,7 @@
   int i = 0;
 
   // For reference of available Boost.Test macros, see
-  // http://www.boost.org/doc/libs/1_54_0/libs/test/doc/html/utf/testing-tools/reference.html
+  // https://www.boost.org/doc/libs/1_58_0/libs/test/doc/html/utf/testing-tools/reference.html
 
   BOOST_CHECK_EQUAL(i, 0);
   BOOST_CHECK_GT(++i, 0);