diff --git a/ethtool-copy.h b/ethtool-copy.h
index 3027ca3..0e90e9b 100644
--- a/ethtool-copy.h
+++ b/ethtool-copy.h
@@ -913,6 +913,10 @@ enum ethtool_sfeatures_retval_bits {
 #define SUPPORTED_10000baseR_FEC	(1 << 20)
 #define SUPPORTED_20000baseMLD2_Full	(1 << 21)
 #define SUPPORTED_20000baseKR2_Full	(1 << 22)
+#define SUPPORTED_40000baseKR4_Full	(1 << 23)
+#define SUPPORTED_40000baseCR4_Full	(1 << 24)
+#define SUPPORTED_40000baseSR4_Full	(1 << 25)
+#define SUPPORTED_40000baseLR4_Full	(1 << 26)
 
 /* Indicates what features are advertised by the interface. */
 #define ADVERTISED_10baseT_Half		(1 << 0)
@@ -938,6 +942,10 @@ enum ethtool_sfeatures_retval_bits {
 #define ADVERTISED_10000baseR_FEC	(1 << 20)
 #define ADVERTISED_20000baseMLD2_Full	(1 << 21)
 #define ADVERTISED_20000baseKR2_Full	(1 << 22)
+#define ADVERTISED_40000baseKR4_Full	(1 << 23)
+#define ADVERTISED_40000baseCR4_Full	(1 << 24)
+#define ADVERTISED_40000baseSR4_Full	(1 << 25)
+#define ADVERTISED_40000baseLR4_Full	(1 << 26)
 
 /* The following are all involved in forcing a particular link
  * mode for the device for setting things.  When getting the
diff --git a/ethtool.c b/ethtool.c
index b0d3eea..6e9418e 100644
--- a/ethtool.c
+++ b/ethtool.c
@@ -460,6 +460,10 @@ dump_link_caps(const char *prefix, const char *an_prefix, u32 mask)
 		{ 0, ADVERTISED_10000baseT_Full,    "10000baseT/Full" },
 		{ 0, ADVERTISED_10000baseKX4_Full,  "10000baseKX4/Full" },
 		{ 0, ADVERTISED_20000baseMLD2_Full, "20000baseMLD2/Full" },
+		{ 0, ADVERTISED_40000baseKR4_Full,  "40000baseKR4/Full" },
+		{ 0, ADVERTISED_40000baseCR4_Full,  "40000baseCR4/Full" },
+		{ 0, ADVERTISED_40000baseSR4_Full,  "40000baseSR4/Full" },
+		{ 0, ADVERTISED_40000baseLR4_Full,  "40000baseLR4/Full" },
 	};
 	int indent;
 	int did1, new_line_pend, i;