diff --git a/console_win.go b/console_win.go
index 8dee86a..bbe8f7b 100644
--- a/console_win.go
+++ b/console_win.go
@@ -168,8 +168,8 @@ const (
 	vtCurlyUnderline          = "\x1b[4:3m"
 	vtDottedUnderline         = "\x1b[4:4m"
 	vtDashedUnderline         = "\x1b[4:5m"
-	vtUnderColor              = "\x1b[58;5;%dm"
-	vtUnderColorRGB           = "\x1b[58;2;%d;%d;%dm"
+	vtUnderColor              = "\x1b[58:5:%dm"
+	vtUnderColorRGB           = "\x1b[58:2::%p1%d:%p2%d:%p3%dm"
 	vtUnderColorReset         = "\x1b[59m"
 )
 
diff --git a/tscreen.go b/tscreen.go
index b9ec768..7be2dab 100644
--- a/tscreen.go
+++ b/tscreen.go
@@ -379,7 +379,7 @@ func (t *tScreen) prepareUnderlines() {
 	if t.ti.UnderlineColor != "" {
 		t.underColor = t.ti.UnderlineColor
 	} else if t.ti.CurlyUnderline != "" {
-		t.underColor = "\x1b[58;5;%p1%dm"
+		t.underColor = "\x1b[58:5:%p1%dm"
 	}
 	if t.ti.UnderlineColorRGB != "" {
 		// An interesting wart here is that in order to facilitate
@@ -389,7 +389,7 @@ func (t *tScreen) prepareUnderlines() {
 		// ncurses took, even though everyone else when another way.
 		t.underRGB = t.ti.UnderlineColorRGB
 	} else if t.ti.CurlyUnderline != "" {
-		t.underRGB = "\x1b[58;2;%p1%d;%p2%d;%p3%dm"
+		t.underRGB = "\x1b[58:2::%p1%d:%p2%d:%p3%dm"
 	}
 	if t.ti.UnderlineColorReset != "" {
 		t.underFg = t.ti.UnderlineColorReset