diff --git a/daemon/face/ethernet-protocol.cpp b/daemon/face/ethernet-protocol.cpp
index 137ff27..3d96d17 100644
--- a/daemon/face/ethernet-protocol.cpp
+++ b/daemon/face/ethernet-protocol.cpp
@@ -33,7 +33,7 @@
 checkFrameHeader(span<const uint8_t> packet, const Address& localAddr, const Address& destAddr)
 {
   if (packet.size() < HDR_LEN + MIN_DATA_LEN)
-    return {nullptr, "Received frame too short: " + to_string(packet.size()) + " bytes"};
+    return {nullptr, "Received frame too short: " + std::to_string(packet.size()) + " bytes"};
 
   const ether_header* eh = reinterpret_cast<const ether_header*>(packet.data());
 
@@ -41,7 +41,7 @@
   // make sure we do not process those frames (see #3348)
   uint16_t ethertype = boost::endian::big_to_native(eh->ether_type);
   if (ethertype != ETHERTYPE_NDN)
-    return {nullptr, "Received frame with wrong ethertype: " + to_string(ethertype)};
+    return {nullptr, "Received frame with wrong ethertype: " + std::to_string(ethertype)};
 
 #ifndef NDEBUG
   Address shost(eh->ether_shost);