diff --git a/cmake/packages.cmake b/cmake/packages.cmake
index 26bb563..4ea4f40 100644
--- a/cmake/packages.cmake
+++ b/cmake/packages.cmake
@@ -4,6 +4,9 @@ set(CPACK_PACKAGE_VERSION_MINOR ${${PROJECT_NAME}_VERSION_MINOR})
 set(CPACK_PACKAGE_VERSION_PATCH ${${PROJECT_NAME}_VERSION_PATCH})
 set(CPACK_PACKAGE_VERSION ${mastodon-cpp_VERSION})
 set(CPACK_PACKAGE_DESCRIPTION_SUMMARY "${PROJECT_DESCRIPTION}")
+if(CPACK_PACKAGE_DESCRIPTION_SUMMARY STREQUAL "") # CMake < 3.9
+  set(CPACK_PACKAGE_DESCRIPTION_SUMMARY "C++ wrapper for the Mastodon API.")
+endif()
 set(CPACK_PACKAGE_CONTACT "tastytea <tastytea@tastytea.de>")
 set(CPACK_RESOURCE_FILE_LICENSE "${PROJECT_SOURCE_DIR}/LICENSE")
 set(CPACK_RESOURCE_FILE_README "${PROJECT_SOURCE_DIR}/README.adoc")