diff --git a/src/BugsnagUnity.mm b/src/BugsnagUnity.mm
index 0ea7571c7..58b94a016 100644
--- a/src/BugsnagUnity.mm
+++ b/src/BugsnagUnity.mm
@@ -18,7 +18,7 @@
   const char *bugsnag_getReleaseStage(const void *configuration);
 
   void bugsnag_setNotifyReleaseStages(const void *configuration, const char *releaseStages[], int releaseStagesCount);
-  void bugsnag_getNotifyReleaseStages(const void *configuration, const void *managedConfiguration, void (*callback)(const void *instance, const char *releaseStages[], NSUInteger size));
+  void bugsnag_getNotifyReleaseStages(const void *configuration, const void *managedConfiguration, void (*callback)(const void *instance, const char *releaseStages[], int size));
 
   void bugsnag_setAppVersion(const void *configuration, char *appVersion);
   const char *bugsnag_getAppVersion(const void *configuration);
@@ -35,7 +35,7 @@
 
   void *bugsnag_createBreadcrumbs(const void *configuration);
   void bugsnag_addBreadcrumb(const void *breadcrumbs, char *name, char *type, char *metadata[], int metadataCount);
-  void bugsnag_retrieveBreadcrumbs(const void *breadcrumbs, const void *managedBreadcrumbs, void (*breadcrumb)(const void *instance, const char *name, const char *timestamp, const char *type, const char *keys[], NSUInteger keys_size, const char *values[], NSUInteger values_size));
+  void bugsnag_retrieveBreadcrumbs(const void *breadcrumbs, const void *managedBreadcrumbs, void (*breadcrumb)(const void *instance, const char *name, const char *timestamp, const char *type, const char *keys[], int keys_size, const char *values[], int values_size));
 
   void bugsnag_retrieveAppData(const void *appData, void (*callback)(const void *instance, const char *key, const char *value));
   void bugsnag_retrieveDeviceData(const void *deviceData, void (*callback)(const void *instance, const char *key, const char *value));
@@ -71,12 +71,17 @@ void bugsnag_setNotifyReleaseStages(const void *configuration, const char *relea
   ((__bridge BugsnagConfiguration *)configuration).notifyReleaseStages = ns_releaseStages;
 }
 
-void bugsnag_getNotifyReleaseStages(const void *configuration, const void *managedConfiguration, void (*callback)(const void *instance, const char *releaseStages[], NSUInteger size)) {
+void bugsnag_getNotifyReleaseStages(const void *configuration, const void *managedConfiguration, void (*callback)(const void *instance, const char *releaseStages[], int size)) {
   NSArray *releaseStages = ((__bridge BugsnagConfiguration *)configuration).notifyReleaseStages;
-  NSUInteger count = [releaseStages count];
+  int count = 0;
+
+  if ([releaseStages count] <= INT_MAX) {
+    count = (int)[releaseStages count];
+  }
+
   const char **c_releaseStages = (const char **) malloc(sizeof(char *) * (count + 1));
 
-  for (NSUInteger i = 0; i < count; i++) {
+  for (int i = 0; i < count; i++) {
     c_releaseStages[i] = [[releaseStages objectAtIndex: i] UTF8String];
   }
 
@@ -167,7 +172,7 @@ void bugsnag_addBreadcrumb(const void *breadcrumbs, char *name, char *type, char
   }];
 }
 
-void bugsnag_retrieveBreadcrumbs(const void *breadcrumbs, const void *managedBreadcrumbs, void (*breadcrumb)(const void *instance, const char *name, const char *timestamp, const char *type, const char *keys[], NSUInteger keys_size, const char *values[], NSUInteger values_size)) {
+void bugsnag_retrieveBreadcrumbs(const void *breadcrumbs, const void *managedBreadcrumbs, void (*breadcrumb)(const void *instance, const char *name, const char *timestamp, const char *type, const char *keys[], int keys_size, const char *values[], int values_size)) {
   NSArray *crumbs = [((__bridge BugsnagBreadcrumbs *) breadcrumbs) arrayValue];
   [crumbs enumerateObjectsUsingBlock:^(id crumb, NSUInteger index, BOOL *stop){
     const char *name = [[crumb valueForKey: @"name"] UTF8String];
@@ -179,11 +184,16 @@ void bugsnag_retrieveBreadcrumbs(const void *breadcrumbs, const void *managedBre
     NSArray *keys = [metadata allKeys];
     NSArray *values = [metadata allValues];
 
-    NSUInteger count = [keys count];
+    int count = 0;
+
+    if ([keys count] <= INT_MAX) {
+      count = (int)[keys count];
+    }
+
     const char **c_keys = (const char **) malloc(sizeof(char *) * (count + 1));
     const char **c_values = (const char **) malloc(sizeof(char *) * (count + 1));
 
-    for (NSUInteger i = 0; i < count; i++) {
+    for (int i = 0; i < count; i++) {
       c_keys[i] = [[keys objectAtIndex: i] UTF8String];
       c_values[i] = [[values objectAtIndex: i] UTF8String];
     }
diff --git a/src/BugsnagUnity/Native/Cocoa/Breadcrumbs.cs b/src/BugsnagUnity/Native/Cocoa/Breadcrumbs.cs
index 5e4479dee..2fac83339 100644
--- a/src/BugsnagUnity/Native/Cocoa/Breadcrumbs.cs
+++ b/src/BugsnagUnity/Native/Cocoa/Breadcrumbs.cs
@@ -83,7 +83,7 @@ public Breadcrumb[] Retrieve()
     }
 
     [MonoPInvokeCallback(typeof(NativeCode.BreadcrumbInformation))]
-    static void PopulateBreadcrumb(IntPtr instance, string name, string timestamp, string type, string[] keys, long keysSize, string[] values, long valuesSize)
+    static void PopulateBreadcrumb(IntPtr instance, string name, string timestamp, string type, string[] keys, int keysSize, string[] values, int valuesSize)
     {
       var handle = GCHandle.FromIntPtr(instance);
       if (handle.Target is List<Breadcrumb> breadcrumbs)
diff --git a/src/BugsnagUnity/Native/Cocoa/NativeCode.cs b/src/BugsnagUnity/Native/Cocoa/NativeCode.cs
index c8b4936f2..edc537c11 100644
--- a/src/BugsnagUnity/Native/Cocoa/NativeCode.cs
+++ b/src/BugsnagUnity/Native/Cocoa/NativeCode.cs
@@ -70,7 +70,7 @@ partial class NativeCode
     [DllImport(Import)]
     internal static extern void bugsnag_addBreadcrumb(IntPtr breadcrumbs, string name, string type, string[] metadata, int metadataCount);
 
-    internal delegate void BreadcrumbInformation(IntPtr instance, string name, string timestamp, string type, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 5)]string[] keys, long keysSize, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 7)]string[] values, long valuesSize);
+    internal delegate void BreadcrumbInformation(IntPtr instance, string name, string timestamp, string type, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 5)]string[] keys, int keysSize, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 7)]string[] values, int valuesSize);
 
     [DllImport(Import)]
     internal static extern void bugsnag_retrieveBreadcrumbs(IntPtr breadcrumbs, IntPtr instance, BreadcrumbInformation visitor);