diff --git a/tek4010 b/tek4010
index 4e655ee..d9c6dde 100755
Binary files a/tek4010 and b/tek4010 differ
diff --git a/tube.c b/tube.c
index 06cca46..3230379 100755
--- a/tube.c
+++ b/tube.c
@@ -48,6 +48,7 @@
 #include <sys/time.h>
 #include <locale.h>
 #include <pwd.h>
+// Cygwin defines FIONREAD in <sys/socket.h>. #26
 #ifndef FIONREAD
 #include <sys/socket.h>
 #endif
@@ -287,7 +288,7 @@ void tube_init(int argc, char* argv[])
         char *argv2[20];
         size_t bufsize = 127;
         int firstArg = 1;
-        printf("tek4010 version 1.5.7b\n");
+        printf("tek4010 version 1.6\n");
         windowName = "Tektronix 4010/4014 emulator";
         if ((argc<2) || (argc>19)) {
                 printf("Error:number of arguments\n");
diff --git a/versions.txt b/versions.txt
index e6c5358..031491f 100644
--- a/versions.txt
+++ b/versions.txt
@@ -1,3 +1,7 @@
+Version 1.6 of January 25, 2021
+===============================
+- Cygwin defines FIONREAD in <sys/socket.h>.
+
 Version 1.5.7b of January 27, 2020
 ==================================
 - ESC FF clears the screen, FF alone does not, as in the original hardware