diff --git a/lottie-ios/Classes/Models/LOTAsset.h b/lottie-ios/Classes/Models/LOTAsset.h
index d1cffd859d..cdd4c7746e 100644
--- a/lottie-ios/Classes/Models/LOTAsset.h
+++ b/lottie-ios/Classes/Models/LOTAsset.h
@@ -9,6 +9,8 @@
 #import <Foundation/Foundation.h>
 #import <CoreGraphics/CoreGraphics.h>
 
+NS_ASSUME_NONNULL_BEGIN
+
 @class LOTLayerGroup;
 @class LOTLayer;
 @class LOTAssetGroup;
@@ -20,13 +22,15 @@
                withFramerate:(NSNumber * _Nullable)framerate
               withAssetGroup:(LOTAssetGroup * _Nullable)assetGroup;
 
-@property (nonatomic, readonly) NSString *referenceID;
-@property (nonatomic, readonly) NSNumber *assetWidth;
-@property (nonatomic, readonly) NSNumber *assetHeight;
+@property (nonatomic, readonly, nullable) NSString *referenceID;
+@property (nonatomic, readonly, nullable) NSNumber *assetWidth;
+@property (nonatomic, readonly, nullable) NSNumber *assetHeight;
 
-@property (nonatomic, readonly) NSString *imageName;
-@property (nonatomic, readonly) NSString *imageDirectory;
+@property (nonatomic, readonly, nullable) NSString *imageName;
+@property (nonatomic, readonly, nullable) NSString *imageDirectory;
 
-@property (nonatomic, readonly) LOTLayerGroup *layerGroup;
+@property (nonatomic, readonly, nullable) LOTLayerGroup *layerGroup;
 
 @end
+
+NS_ASSUME_NONNULL_END
diff --git a/lottie-ios/Classes/Models/LOTLayerGroup.h b/lottie-ios/Classes/Models/LOTLayerGroup.h
index b723546a9c..48b31dff5f 100644
--- a/lottie-ios/Classes/Models/LOTLayerGroup.h
+++ b/lottie-ios/Classes/Models/LOTLayerGroup.h
@@ -9,6 +9,8 @@
 #import <Foundation/Foundation.h>
 #import <CoreGraphics/CoreGraphics.h>
 
+NS_ASSUME_NONNULL_BEGIN
+
 @class LOTLayer;
 @class LOTAssetGroup;
 
@@ -16,7 +18,7 @@
 
 - (instancetype)initWithLayerJSON:(NSArray *)layersJSON
                        withBounds:(CGRect)bounds
-                    withFramerate:(NSNumber *)framerate
+                    withFramerate:(NSNumber * _Nullable)framerate
                    withAssetGroup:(LOTAssetGroup * _Nullable)assetGroup;
 
 @property (nonatomic, readonly) NSArray <LOTLayer *> *layers;
@@ -25,3 +27,5 @@
 - (LOTLayer *)layerForReferenceID:(NSString *)referenceID;
 
 @end
+
+NS_ASSUME_NONNULL_END
diff --git a/lottie-ios/Classes/Private/LOTAnimationView_Internal.h b/lottie-ios/Classes/Private/LOTAnimationView_Internal.h
index ccc3c320d6..7ea8e5169a 100644
--- a/lottie-ios/Classes/Private/LOTAnimationView_Internal.h
+++ b/lottie-ios/Classes/Private/LOTAnimationView_Internal.h
@@ -16,7 +16,7 @@ typedef enum : NSUInteger {
 
 @interface LOTAnimationState : NSObject
 
-- (instancetype)initWithDuration:(CGFloat)duration layer:(CALayer *)layer frameRate:(NSNumber *)framerate;
+- (instancetype _Nonnull)initWithDuration:(CGFloat)duration layer:(CALayer * _Nullable)layer frameRate:(NSNumber * _Nullable)framerate;
 
 - (void)setAnimationIsPlaying:(BOOL)animationIsPlaying;
 - (void)setAnimationDoesLoop:(BOOL)loopAnimation;