diff --git a/IBPCollectionViewCompositionalLayout.podspec b/IBPCollectionViewCompositionalLayout.podspec
index 0cdf32b..81db344 100644
--- a/IBPCollectionViewCompositionalLayout.podspec
+++ b/IBPCollectionViewCompositionalLayout.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name                  = 'IBPCollectionViewCompositionalLayout'
-  s.version               = '0.6.7'
+  s.version               = '0.6.9'
   s.summary               = 'Backport of UICollectionViewCompositionalLayout to earlier iOS 12.'
   s.description           = <<-DESC
                               A new UICollectionViewCompositionalLayout class has been added to UIKit to make it incredibly easier to create custom complex collection view layout.
diff --git a/Sources/IBPCollectionViewCompositionalLayout/IBPUICollectionViewCompositionalLayout.m b/Sources/IBPCollectionViewCompositionalLayout/IBPUICollectionViewCompositionalLayout.m
index 12667d1..a060d7f 100644
--- a/Sources/IBPCollectionViewCompositionalLayout/IBPUICollectionViewCompositionalLayout.m
+++ b/Sources/IBPCollectionViewCompositionalLayout/IBPUICollectionViewCompositionalLayout.m
@@ -136,7 +136,7 @@ - (void)prepareLayout {
         return;
     }
 
-    if (!self.collectionViewDelegate && collectionView.delegate != self) {
+    if (collectionView.collectionViewLayout == self && !self.collectionViewDelegate && collectionView.delegate != self) {
         self.collectionViewDelegate = collectionView.delegate;
         collectionView.delegate = self;
     }
@@ -145,7 +145,7 @@ - (void)prepareLayout {
 
     UIEdgeInsets collectionContentInset = UIEdgeInsetsZero;
     if (@available(iOS 11.0, *)) {
-        if ([collectionView respondsToSelector:@selector(safeAreaInsets)]) {
+        if ([collectionView respondsToSelector:@selector(safeAreaInsets)] && collectionView.contentInsetAdjustmentBehavior != UIScrollViewContentInsetAdjustmentNever) {
             collectionContentInset = collectionView.safeAreaInsets;
         }
     }
@@ -527,7 +527,51 @@ - (UICollectionViewLayoutAttributes *)prepareLayoutForBoundaryItem:(IBPNSCollect
                                                                                                                         withIndexPath:indexPath];
     IBPNSCollectionLayoutContainer *itemContainer = [[IBPNSCollectionLayoutContainer alloc] initWithContentSize:containerFrame.size
                                                                                                   contentInsets:IBPNSDirectionalEdgeInsetsZero];
-    CGSize itemSize = [boundaryItem.layoutSize effectiveSizeForContainer:itemContainer];
+    IBPNSCollectionLayoutSize *layoutSize = boundaryItem.layoutSize;
+    CGSize itemSize;
+
+    if (layoutSize.heightDimension.isEstimated || layoutSize.widthDimension.isEstimated) {
+        UICollectionReusableView *view = [self.collectionView.dataSource collectionView:self.collectionView
+                                                      viewForSupplementaryElementOfKind:boundaryItem.elementKind
+                                                                            atIndexPath:indexPath];
+
+        if (view) {
+            CGSize containerSize = self.collectionViewContentSize;
+
+            if (!layoutSize.widthDimension.isEstimated) {
+                containerSize.width = CGRectGetWidth(containerFrame);
+            }
+            if (!layoutSize.heightDimension.isEstimated) {
+                containerSize.height = CGRectGetHeight(containerFrame);
+            }
+
+            CGFloat containerWidth = containerSize.width;
+            CGFloat containerHeight = containerSize.height;
+
+            CGRect viewFrame = view.frame;
+            viewFrame.size = containerSize;
+            view.frame = viewFrame;
+            [view setNeedsLayout];
+            [view layoutIfNeeded];
+
+            CGSize fitSize;
+            if (layoutSize.widthDimension.isEstimated) {
+                fitSize = [view systemLayoutSizeFittingSize:containerSize
+                              withHorizontalFittingPriority:UILayoutPriorityFittingSizeLevel
+                                    verticalFittingPriority:UILayoutPriorityRequired];
+                fitSize.height = containerHeight;
+            } else {
+                fitSize = [view systemLayoutSizeFittingSize:containerSize
+                              withHorizontalFittingPriority:UILayoutPriorityRequired
+                                    verticalFittingPriority:UILayoutPriorityFittingSizeLevel];
+                fitSize.width = containerWidth;
+            }
+
+            itemSize = fitSize;
+        }
+    } else {
+        itemSize = [boundaryItem.layoutSize effectiveSizeForContainer:itemContainer];
+    }
 
     IBPNSCollectionLayoutAnchor *containerAnchor;
     switch (boundaryItem.alignment) {
@@ -846,7 +890,7 @@ - (void)scrollViewDidChangeAdjustedContentInset:(UIScrollView *)scrollView API_A
 }
 
 - (BOOL)respondsToSelector:(SEL)aSelector {
-    return [self.collectionViewDelegate respondsToSelector:aSelector] || [super respondsToSelector:aSelector];
+    return [self.collectionViewDelegate respondsToSelector:aSelector] || [UICollectionViewLayout instancesRespondToSelector:aSelector];
 }
 
 - (void)forwardInvocation:(NSInvocation *)anInvocation {
diff --git a/Sources/Info.plist b/Sources/Info.plist
index a7b18e1..65609fa 100644
--- a/Sources/Info.plist
+++ b/Sources/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.6.7</string>
+	<string>0.6.9</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 </dict>