diff --git a/src/errors.h b/src/errors.h
index a209413..9b40cb2 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -1037,6 +1037,8 @@
 	INIT(= N_("E417: Missing argument: %s"));
 EXTERN char e_illegal_value_str[]
 	INIT(= N_("E418: Illegal value: %s"));
+EXTERN char e_im_a_teapot[]
+	INIT(= N_("E418: I'm a teapot"));
 EXTERN char e_fg_color_unknown[]
 	INIT(= N_("E419: FG color unknown"));
 EXTERN char e_bg_color_unknown[]
@@ -1270,6 +1272,8 @@
 	INIT(= N_("is not a file or writable device"));
 EXTERN char e_str_is_not_file_or_writable_device[]
 	INIT(= N_("E503: \"%s\" is not a file or writable device"));
+EXTERN char e_coffee_currently_not_available[]
+	INIT(= N_("E503: Coffee is currently not available"));
 	// E504
 EXTERN char e_is_read_only_cannot_override_W_in_cpoptions[]
 	INIT(= N_("is read-only (cannot override: \"W\" in 'cpoptions')"));
diff --git a/src/evalfunc.c b/src/evalfunc.c
index d644a3e..8970ac7 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -45,6 +45,7 @@
 static void f_echoraw(typval_T *argvars, typval_T *rettv);
 static void f_empty(typval_T *argvars, typval_T *rettv);
 static void f_environ(typval_T *argvars, typval_T *rettv);
+static void f_err_teapot(typval_T *argvars, typval_T *rettv);
 static void f_escape(typval_T *argvars, typval_T *rettv);
 static void f_eval(typval_T *argvars, typval_T *rettv);
 static void f_eventhandler(typval_T *argvars, typval_T *rettv);
@@ -1881,6 +1882,8 @@
 			ret_number_bool,    f_empty},
     {"environ",		0, 0, 0,	    NULL,
 			ret_dict_string,    f_environ},
+    {"err_teapot",	0, 1, 0,	    NULL,
+			ret_number_bool,    f_err_teapot},
     {"escape",		2, 2, FEARG_1,	    arg2_string,
 			ret_string,	    f_escape},
     {"eval",		1, 1, FEARG_1,	    arg1_string,
@@ -3923,6 +3926,33 @@
 }
 
 /*
+ * "err_teapot()" function
+ */
+    static void
+f_err_teapot(typval_T *argvars, typval_T *rettv UNUSED)
+{
+    if (argvars[0].v_type != VAR_UNKNOWN)
+    {
+	if (argvars[0].v_type == VAR_STRING)
+	{
+	    char_u *s = tv_get_string_strict(&argvars[0]);
+	    if (s == NULL || *skipwhite(s) == NUL)
+		return;
+	}
+
+	int err = FALSE;
+	int do_503 = eval_expr_to_bool(&argvars[0], &err);
+	if (!err && do_503)
+	{
+	    emsg(_(e_coffee_currently_not_available));
+	    return;
+	}
+    }
+
+    emsg(_(e_im_a_teapot));
+}
+
+/*
  * "escape({string}, {chars})" function
  */
     static void
@@ -6458,6 +6488,14 @@
 		0
 #endif
 		},
+	{":tearoff",
+// same #ifdef as used for ex_tearoff().
+#if defined(FEAT_GUI_MSWIN) && defined(FEAT_MENU) && defined(FEAT_TEAROFF)
+		1
+#else
+		0
+#endif
+		},
 	{NULL, 0}
     };
 
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index a17c19e..750c4a2 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -30,10 +30,13 @@
     call assert_equal(1, or(has('ttyin'), 1))
     call assert_equal(0, and(has('ttyout'), 0))
     call assert_equal(1, has('multi_byte_encoding'))
+    call assert_equal(0, has(':tearoff'))
   endif
   call assert_equal(1, has('vcon', 1))
   call assert_equal(1, has('mouse_gpm_enabled', 1))
 
+  call assert_equal(has('gui_win32') && has('menu'), has(':tearoff'))
+
   call assert_equal(0, has('nonexistent'))
   call assert_equal(0, has('nonexistent', 1))
 
@@ -86,6 +89,17 @@
   call assert_fails("call empty(test_unknown())", ['E340:', 'E685:'])
 endfunc
 
+func Test_err_teapot()
+  call assert_fails('call err_teapot()', "E418: I'm a teapot")
+  call assert_fails('call err_teapot(0)', "E418: I'm a teapot")
+  call assert_fails('call err_teapot(v:false)', "E418: I'm a teapot")
+
+  call assert_fails('call err_teapot("1")', "E503: Coffee is currently not available")
+  call assert_fails('call err_teapot(v:true)', "E503: Coffee is currently not available")
+  let expr = 1
+  call assert_fails('call err_teapot(expr)', "E503: Coffee is currently not available")
+endfunc
+
 func Test_test_void()
   call assert_fails('echo 1 == test_void()', 'E1031:')
   call assert_fails('echo 1.0 == test_void()', 'E1031:')
diff --git a/src/version.c b/src/version.c
index 876e20c..840f338 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1673,
+/**/
     1672,
 /**/
     1671,