diff --git a/Source/Constraint.swift b/Source/Constraint.swift
index b93a8d9..7324c59 100644
--- a/Source/Constraint.swift
+++ b/Source/Constraint.swift
@@ -228,7 +228,17 @@ public class Constraint {
         for layoutConstraint in self.layoutConstraints {
             let attribute = (layoutConstraint.secondAttribute == .notAnAttribute) ? layoutConstraint.firstAttribute : layoutConstraint.secondAttribute
             layoutConstraint.constant = self.constant.constraintConstantTargetValueFor(layoutAttribute: attribute)
-            layoutConstraint.priority = self.priority.constraintPriorityTargetValue
+            
+            #if os(iOS) || os(tvOS)
+                let requiredPriority: UILayoutPriority = UILayoutPriorityRequired
+            #else
+                let requiredPriority: Float = 1000.0
+            #endif
+            
+            
+            if (layoutConstraint.priority < requiredPriority), (self.priority.constraintPriorityTargetValue != requiredPriority) {
+                layoutConstraint.priority = self.priority.constraintPriorityTargetValue
+            }
         }
     }