diff --git a/src/uikit.cs b/src/uikit.cs
index f51e9a56d083..6735d353b800 100644
--- a/src/uikit.cs
+++ b/src/uikit.cs
@@ -445,7 +445,7 @@ public enum UISearchControllerScopeBarActivation : long {
 	///     <summary>Completion handler used with <see cref="UIKit.UIPrinter.ContactPrinter(UIKit.UIPrinterContactPrinterHandler)" />.</summary>
 	delegate void UIPrinterContactPrinterHandler (bool available);
 	/// <summary>Completion handler used with various <see cref="UIKit.UIPrinterPickerController" /> presentation methods.</summary>
-	delegate void UIPrinterPickerCompletionHandler (UIPrinterPickerController printerPickerController, bool userDidSelect, NSError error);
+	delegate void UIPrinterPickerCompletionHandler ([NullAllowed] UIPrinterPickerController printerPickerController, bool userDidSelect, [NullAllowed] NSError error);
 
 	delegate UISplitViewControllerDisplayMode UISplitViewControllerFetchTargetForActionHandler (UISplitViewController svc);
 	delegate bool UISplitViewControllerDisplayEvent (UISplitViewController splitViewController, UIViewController vc, NSObject sender);
@@ -453,7 +453,7 @@ public enum UISearchControllerScopeBarActivation : long {
 	delegate bool UISplitViewControllerCanCollapsePredicate (UISplitViewController splitViewController, UIViewController secondaryViewController, UIViewController primaryViewController);
 	delegate UIViewController UISplitViewControllerGetSecondaryViewController (UISplitViewController splitViewController, UIViewController primaryViewController);
 	/// <summary>The callback executed after a <see cref="UIKit.UIActivityViewController" /> is dismissed.</summary>
-	delegate void UIActivityViewControllerCompletion (NSString activityType, bool completed, NSExtensionItem [] returnedItems, NSError error);
+	delegate void UIActivityViewControllerCompletion ([NullAllowed] NSString activityType, bool completed, [NullAllowed] NSExtensionItem [] returnedItems, [NullAllowed] NSError error);
 
 	// In the hopes that the parameter is self document: this array  can contain either UIDocuments or UIResponders
 	/// <param name="uidocumentOrResponderObjects">To be added.</param>
@@ -1703,6 +1703,7 @@ partial interface UIAccessibilityCustomAction {
 		NSString CategoryEdit { get; }
 	}
 
+	[return: NullAllowed]
 	delegate UIAccessibilityCustomRotorItemResult UIAccessibilityCustomRotorSearch (UIAccessibilityCustomRotorSearchPredicate predicate);
 
 	[MacCatalyst (13, 1)]
@@ -4494,7 +4495,9 @@ public enum UITextSearchMatchMethod : long {
 		FullWord,
 	}
 
+	[return: NullAllowed]
 	delegate UIViewController UIContextMenuContentPreviewProvider ();
+	[return: NullAllowed]
 	delegate UIMenu UIContextMenuActionProvider (UIMenuElement [] suggestedActions);
 
 	[TV (17, 0), iOS (13, 0)]
@@ -12193,6 +12196,7 @@ interface UIBezierPath : NSSecureCoding, NSCopying {
 
 	[NoTV, iOS (13, 4)]
 	[MacCatalyst (13, 1)]
+	[return: NullAllowed]
 	delegate UIPointerStyle UIButtonPointerStyleProvider (UIButton button, UIPointerEffect proposedEffect, UIPointerShape proposedShape);
 
 	[NoTV, iOS (15, 0), MacCatalyst (15, 0)]
@@ -25336,6 +25340,7 @@ interface UIStepper {
 
 	[iOS (13, 0), TV (13, 0)]
 	[MacCatalyst (13, 1)]
+	[return: NullAllowed]
 	delegate UIViewController UIStoryboardViewControllerCreator (NSCoder coder);
 
 	[MacCatalyst (13, 1)]
@@ -26270,7 +26275,7 @@ interface UIPrintInteractionControllerDelegate {
 	}
 
 	/// <summary>A delegate executed after printing completes or after a printing error occurs.</summary>
-	delegate void UIPrintInteractionCompletionHandler (UIPrintInteractionController printInteractionController, bool completed, NSError error);
+	delegate void UIPrintInteractionCompletionHandler ([NullAllowed] UIPrintInteractionController printInteractionController, bool completed, [NullAllowed] NSError error);
 
 	/// <include file="../docs/api/UIKit/UIPrintInteractionController.xml" path="/Documentation/Docs[@DocId='T:UIKit.UIPrintInteractionController']/*" />
 	[NoTV]
@@ -31250,6 +31255,7 @@ interface UICollectionViewCompositionalLayoutConfiguration : NSCopying {
 
 	[TV (13, 0), iOS (13, 0)]
 	[MacCatalyst (13, 1)]
+	[return: NullAllowed]
 	delegate NSCollectionLayoutSection UICollectionViewCompositionalLayoutSectionProvider (nint section, INSCollectionLayoutEnvironment layoutEnvironment);
 
 	[TV (13, 0), iOS (13, 0)]
@@ -31665,7 +31671,7 @@ interface UIScreenshotService {
 
 	[iOS (13, 0), TV (13, 0)]
 	[MacCatalyst (13, 1)]
-	delegate NSDictionary UIScreenshotServiceDelegatePdfHandler (NSData pdfData, nint indexOfCurrentPage, CGRect rectInCurrentPage);
+	delegate NSDictionary UIScreenshotServiceDelegatePdfHandler ([NullAllowed] NSData pdfData, nint indexOfCurrentPage, CGRect rectInCurrentPage);
 
 	interface IUIScreenshotServiceDelegate { }
 
@@ -32120,10 +32126,12 @@ interface UITabBarItemAppearance : NSCopying, NSSecureCoding {
 
 	[TV (13, 0), iOS (13, 0)]
 	[MacCatalyst (13, 1)]
+	[return: NullAllowed]
 	delegate UICollectionViewCell UICollectionViewDiffableDataSourceCellProvider (UICollectionView collectionView, NSIndexPath indexPath, NSObject itemIdentifier);
 
 	[TV (13, 0), iOS (13, 0)]
 	[MacCatalyst (13, 1)]
+	[return: NullAllowed]
 	delegate UICollectionReusableView UICollectionViewDiffableDataSourceSupplementaryViewProvider (UICollectionView collectionView, string elementKind, NSIndexPath indexPath);
 
 	[TV (13, 0), iOS (13, 0)]
@@ -32204,6 +32212,7 @@ interface UICollectionViewDiffableDataSource<SectionIdentifierType, ItemIdentifi
 
 	[TV (13, 0), iOS (13, 0)]
 	[MacCatalyst (13, 1)]
+	[return: NullAllowed]
 	delegate UITableViewCell UITableViewDiffableDataSourceCellProvider (UITableView tableView, NSIndexPath indexPath, NSObject obj);
 
 	[TV (13, 0), iOS (13, 0)]
@@ -32280,8 +32289,11 @@ interface UIActivityItemsConfigurationMetadataKey {
 		NSString ShareRecipients { get; }
 	}
 
+	[return: NullAllowed]
 	delegate NSObject UIActivityItemsConfigurationMetadataProviderHandler (NSString activityItemsConfigurationMetadataKey);
+	[return: NullAllowed]
 	delegate NSObject UIActivityItemsConfigurationPerItemMetadataProviderHandler (nint index, NSString activityItemsConfigurationMetadataKey);
+	[return: NullAllowed]
 	delegate NSObject UIActivityItemsConfigurationPreviewProviderHandler (nint index, NSString activityItemsConfigurationPreviewIntent, CGSize suggestedSize);
 
 	[NoTV, iOS (13, 0)]
@@ -32986,6 +32998,7 @@ interface UICellConfigurationState {
 
 	[NoTV]
 	[MacCatalyst (13, 1)]
+	[return: NullAllowed]
 	delegate UISwipeActionsConfiguration UICollectionLayoutListSwipeActionsConfigurationProvider (NSIndexPath indexPath);
 
 	[NoTV]
@@ -34391,6 +34404,7 @@ interface UITrackingLayoutGuide {
 	}
 
 	[NoTV, iOS (15, 0), MacCatalyst (15, 0)]
+	[return: NullAllowed]
 	delegate UIWindowSceneActivationConfiguration UIWindowSceneActivationActionConfigurationProvider (UIWindowSceneActivationAction action);
 
 	[NoTV, iOS (15, 0), MacCatalyst (15, 0)]
@@ -34426,6 +34440,7 @@ interface UIWindowSceneActivationConfiguration {
 	}
 
 	[NoTV, iOS (15, 0), MacCatalyst (15, 0)]
+	[return: NullAllowed]
 	delegate UIWindowSceneActivationConfiguration UIWindowSceneActivationInteractionConfigurationProvider (UIWindowSceneActivationInteraction interaction, CGPoint location);
 
 	[NoTV, iOS (15, 0), MacCatalyst (15, 0)]
@@ -35016,6 +35031,7 @@ interface UIDocumentProperties {
 	}
 
 	[NoTV, iOS (16, 0), MacCatalyst (16, 0)]
+	[return: NullAllowed]
 	delegate UIMenu OptionsMenuProviderHandler (UIMenuElement [] elements);
 
 	[NoTV, iOS (16, 0), MacCatalyst (16, 0)]
@@ -37788,6 +37804,7 @@ interface NSUIViewToolbarItem {
 	}
 
 	[NoMac, NoTV, iOS (18, 1), MacCatalyst (18, 1)]
+	[return: NullAllowed]
 	delegate IUITextInput UITextInputReturnHandler ();
 
 	[NoMac, NoTV, iOS (18, 1), MacCatalyst (18, 1)]
diff --git a/src/xkit.cs b/src/xkit.cs
index fe2fe27098a4..fcaf0ed7b446 100644
--- a/src/xkit.cs
+++ b/src/xkit.cs
@@ -3842,7 +3842,7 @@ interface INSTextLayoutManagerDelegate { }
 	delegate bool NSTextLayoutManagerEnumerateRenderingAttributesDelegate (NSTextLayoutManager textLayoutManager, NSDictionary<NSString, NSObject> attributes, NSTextRange textRange);
 
 	[TV (15, 0), iOS (15, 0), MacCatalyst (15, 0)]
-	delegate bool NSTextLayoutManagerEnumerateTextSegmentsDelegate (NSTextRange textSegmentRange, CGRect textSegmentFrame, nfloat baselinePosition, NSTextContainer textContainer);
+	delegate bool NSTextLayoutManagerEnumerateTextSegmentsDelegate ([NullAllowed] NSTextRange textSegmentRange, CGRect textSegmentFrame, nfloat baselinePosition, NSTextContainer textContainer);
 
 	[TV (15, 0), iOS (15, 0), MacCatalyst (15, 0)]
 	[DesignatedDefaultCtor]
@@ -4409,7 +4409,7 @@ interface NSTextSelection : NSSecureCoding {
 	}
 
 	[TV (15, 0), iOS (15, 0), MacCatalyst (15, 0)]
-	delegate void NSTextSelectionDataSourceEnumerateSubstringsDelegate (NSString substring, NSTextRange substringRange, NSTextRange enclodingRange, out bool stop);
+	delegate void NSTextSelectionDataSourceEnumerateSubstringsDelegate ([NullAllowed] NSString substring, NSTextRange substringRange, [NullAllowed] NSTextRange enclodingRange, out bool stop);
 
 	[TV (15, 0), iOS (15, 0), MacCatalyst (15, 0)]
 	delegate void NSTextSelectionDataSourceEnumerateCaretOffsetsDelegate (nfloat caretOffset, INSTextLocation location, bool leadingEdge, out bool stop);