diff --git a/daemon/fw/strategy.hpp b/daemon/fw/strategy.hpp
index b52c05b..0df65b9 100644
--- a/daemon/fw/strategy.hpp
+++ b/daemon/fw/strategy.hpp
@@ -336,7 +336,7 @@
   struct ParsedInstanceName
   {
     Name strategyName; ///< strategy name without parameters
-    ndn::optional<uint64_t> version; ///< whether strategyName contains a version component
+    optional<uint64_t> version; ///< whether strategyName contains a version component
     PartialName parameters; ///< parameter components
   };