diff --git a/spine-csharp/src/PhysicsConstraint.cs b/spine-csharp/src/PhysicsConstraint.cs
index 277c3da3a..aede953ec 100644
--- a/spine-csharp/src/PhysicsConstraint.cs
+++ b/spine-csharp/src/PhysicsConstraint.cs
@@ -170,7 +170,7 @@ namespace Spine {
 							uy = by;
 						}
 						if (a >= t) {
-							float m = massInverse * t, e = strength, w = wind * f, g = gravity * f;
+							float m = massInverse * t, e = strength, w = wind * f, g = (Bone.yDown ? -gravity : gravity) * f;
 							float d = (float)Math.Pow(damping, 60 * t);
 							do {
 								if (x) {
@@ -219,7 +219,7 @@ namespace Spine {
 						}
 						a = this.remaining;
 						if (a >= t) {
-							float m = massInverse * t, e = strength, w = wind, g = gravity;
+							float m = massInverse * t, e = strength, w = wind, g = (Bone.yDown ? -gravity : gravity);
 							float d = (float)Math.Pow(damping, 60 * t), h = l / f;
 							while (true) {
 								a -= t;
diff --git a/spine-csharp/src/package.json b/spine-csharp/src/package.json
index 6479e8467..78cdf16e5 100644
--- a/spine-csharp/src/package.json
+++ b/spine-csharp/src/package.json
@@ -2,7 +2,7 @@
 	"name": "com.esotericsoftware.spine.spine-csharp",
 	"displayName": "spine-csharp Runtime",
 	"description": "This plugin provides the spine-csharp core runtime.",
-	"version": "4.2.18",
+	"version": "4.2.19",
 	"unity": "2018.3",
 	"author": {
 		"name": "Esoteric Software",