diff --git a/src/lceasy.c b/src/lceasy.c
index 41874d3..7d0b6d2 100644
--- a/src/lceasy.c
+++ b/src/lceasy.c
@@ -4,6 +4,7 @@
 #include "lcutils.h"
 #include "lchttppost.h"
 #include "lcshare.h"
+#include <memory.h>
 
 static const char *LCURL_ERROR_TAG = "LCURL_ERROR_TAG";
 
@@ -677,7 +678,13 @@ static int lcurl_easy_getinfo(lua_State *L){
   }
 #undef OPT_ENTRY
 
-  return lcurl_fail_ex(L, p->err_mode, LCURL_ERROR_EASY, CURLE_UNKNOWN_OPTION);
+  return lcurl_fail_ex(L, p->err_mode, LCURL_ERROR_EASY, 
+#if LCURL_CURL_VER_GE(7,21,5)
+  CURLE_UNKNOWN_OPTION
+#else
+  CURLE_UNKNOWN_TELNET_OPTION
+#endif
+  );
 }
 
 //}