diff --git a/atom/browser/browser_mac.mm b/atom/browser/browser_mac.mm
index 70bddd1500ce..dfbdf710d452 100644
--- a/atom/browser/browser_mac.mm
+++ b/atom/browser/browser_mac.mm
@@ -142,13 +142,9 @@ void Browser::SetUserActivity(const std::string& type,
 }
 
 std::string Browser::GetCurrentActivityType() {
-  if (@available(macOS 10.10, *)) {
-    NSUserActivity* userActivity =
-        [[AtomApplication sharedApplication] getCurrentActivity];
-    return base::SysNSStringToUTF8(userActivity.activityType);
-  } else {
-    return std::string();
-  }
+  NSUserActivity* userActivity =
+      [[AtomApplication sharedApplication] getCurrentActivity];
+  return base::SysNSStringToUTF8(userActivity.activityType);
 }
 
 void Browser::InvalidateCurrentActivity() {
diff --git a/atom/browser/mac/atom_application.h b/atom/browser/mac/atom_application.h
index b0a8742ee98b..5015608d6fc6 100644
--- a/atom/browser/mac/atom_application.h
+++ b/atom/browser/mac/atom_application.h
@@ -11,7 +11,7 @@
                                             NSUserActivityDelegate> {
  @private
   BOOL handlingSendEvent_;
-  base::scoped_nsobject<NSUserActivity> currentActivity_ API_AVAILABLE(macosx(10.10));
+  base::scoped_nsobject<NSUserActivity> currentActivity_;
   NSCondition* handoffLock_;
   BOOL updateReceived_;
   base::Callback<bool()> shouldShutdown_;
@@ -27,7 +27,7 @@
 // CrAppControlProtocol:
 - (void)setHandlingSendEvent:(BOOL)handlingSendEvent;
 
-- (NSUserActivity*)getCurrentActivity API_AVAILABLE(macosx(10.10));
+- (NSUserActivity*)getCurrentActivity;
 - (void)setCurrentActivity:(NSString*)type
               withUserInfo:(NSDictionary*)userInfo
             withWebpageURL:(NSURL*)webpageURL;
diff --git a/atom/browser/mac/atom_application.mm b/atom/browser/mac/atom_application.mm
index eb00a415bf24..226c09091bc8 100644
--- a/atom/browser/mac/atom_application.mm
+++ b/atom/browser/mac/atom_application.mm
@@ -58,15 +58,13 @@ inline void dispatch_sync_main(dispatch_block_t block) {
 - (void)setCurrentActivity:(NSString*)type
               withUserInfo:(NSDictionary*)userInfo
             withWebpageURL:(NSURL*)webpageURL {
-  if (@available(macOS 10.10, *)) {
-    currentActivity_ = base::scoped_nsobject<NSUserActivity>(
-        [[NSUserActivity alloc] initWithActivityType:type]);
-    [currentActivity_ setUserInfo:userInfo];
-    [currentActivity_ setWebpageURL:webpageURL];
-    [currentActivity_ setDelegate:self];
-    [currentActivity_ becomeCurrent];
-    [currentActivity_ setNeedsSave:YES];
-  }
+  currentActivity_ = base::scoped_nsobject<NSUserActivity>(
+      [[NSUserActivity alloc] initWithActivityType:type]);
+  [currentActivity_ setUserInfo:userInfo];
+  [currentActivity_ setWebpageURL:webpageURL];
+  [currentActivity_ setDelegate:self];
+  [currentActivity_ becomeCurrent];
+  [currentActivity_ setNeedsSave:YES];
 }
 
 - (NSUserActivity*)getCurrentActivity {
@@ -92,8 +90,7 @@ inline void dispatch_sync_main(dispatch_block_t block) {
   [handoffLock_ unlock];
 }
 
-- (void)userActivityWillSave:(NSUserActivity*)userActivity
-    API_AVAILABLE(macosx(10.10)) {
+- (void)userActivityWillSave:(NSUserActivity*)userActivity {
   __block BOOL shouldWait = NO;
   dispatch_sync_main(^{
     std::string activity_type(
@@ -121,8 +118,7 @@ inline void dispatch_sync_main(dispatch_block_t block) {
   [userActivity setNeedsSave:YES];
 }
 
-- (void)userActivityWasContinued:(NSUserActivity*)userActivity
-    API_AVAILABLE(macosx(10.10)) {
+- (void)userActivityWasContinued:(NSUserActivity*)userActivity {
   dispatch_async(dispatch_get_main_queue(), ^{
     std::string activity_type(
         base::SysNSStringToUTF8(userActivity.activityType));
diff --git a/atom/browser/mac/atom_application_delegate.mm b/atom/browser/mac/atom_application_delegate.mm
index 683f7a84bcaa..8dfa6e81a073 100644
--- a/atom/browser/mac/atom_application_delegate.mm
+++ b/atom/browser/mac/atom_application_delegate.mm
@@ -98,8 +98,7 @@ static base::mac::ScopedObjCClassSwizzler* g_swizzle_imk_input_session;
 - (BOOL)application:(NSApplication*)sender
     continueUserActivity:(NSUserActivity*)userActivity
       restorationHandler:
-          (void (^)(NSArray* restorableObjects))restorationHandler
-    API_AVAILABLE(macosx(10.10)) {
+          (void (^)(NSArray* restorableObjects))restorationHandler {
   std::string activity_type(base::SysNSStringToUTF8(userActivity.activityType));
   std::unique_ptr<base::DictionaryValue> user_info =
       atom::NSDictionaryToDictionaryValue(userActivity.userInfo);
diff --git a/atom/browser/native_window_mac.h b/atom/browser/native_window_mac.h
index dd343c6e2a20..bbaee5f1d672 100644
--- a/atom/browser/native_window_mac.h
+++ b/atom/browser/native_window_mac.h
@@ -153,8 +153,6 @@ class NativeWindowMac : public NativeWindow {
 
  private:
   void InternalSetParentWindow(NativeWindow* parent, bool attach);
-  void ShowWindowButton(NSWindowButton button);
-
   void SetForwardMouseMessages(bool forward);
 
   AtomNSWindow* window_;  // Weak ref, managed by widget_.
diff --git a/atom/browser/native_window_mac.mm b/atom/browser/native_window_mac.mm
index ba28d4f501bd..6f808936ebca 100644
--- a/atom/browser/native_window_mac.mm
+++ b/atom/browser/native_window_mac.mm
@@ -295,11 +295,9 @@ NativeWindowMac::NativeWindowMac(const mate::Dictionary& options,
   }
 
   NSUInteger styleMask = NSTitledWindowMask;
-  if (@available(macOS 10.10, *)) {
-    if (title_bar_style_ == CUSTOM_BUTTONS_ON_HOVER &&
-        (!useStandardWindow || transparent() || !has_frame())) {
-      styleMask = NSFullSizeContentViewWindowMask;
-    }
+  if (title_bar_style_ == CUSTOM_BUTTONS_ON_HOVER &&
+      (!useStandardWindow || transparent() || !has_frame())) {
+    styleMask = NSFullSizeContentViewWindowMask;
   }
   if (minimizable) {
     styleMask |= NSMiniaturizableWindowMask;
@@ -354,11 +352,10 @@ NativeWindowMac::NativeWindowMac(const mate::Dictionary& options,
     [window_ setDisableKeyOrMainWindow:YES];
 
   if (transparent() || !has_frame()) {
-    if (@available(macOS 10.10, *)) {
-      // Don't show title bar.
-      [window_ setTitlebarAppearsTransparent:YES];
-      [window_ setTitleVisibility:NSWindowTitleHidden];
-    }
+    // Don't show title bar.
+    [window_ setTitlebarAppearsTransparent:YES];
+    [window_ setTitleVisibility:NSWindowTitleHidden];
+
     // Remove non-transparent corners, see http://git.io/vfonD.
     [window_ setOpaque:NO];
   }
@@ -377,22 +374,15 @@ NativeWindowMac::NativeWindowMac(const mate::Dictionary& options,
 
   // Hide the title bar background
   if (title_bar_style_ != NORMAL) {
-    if (@available(macOS 10.10, *)) {
-      [window_ setTitlebarAppearsTransparent:YES];
-    }
+    [window_ setTitlebarAppearsTransparent:YES];
   }
 
   // Hide the title bar.
   if (title_bar_style_ == HIDDEN_INSET) {
-    if (@available(macOS 10.10, *)) {
-      base::scoped_nsobject<NSToolbar> toolbar(
-          [[NSToolbar alloc] initWithIdentifier:@"titlebarStylingToolbar"]);
-      [toolbar setShowsBaselineSeparator:NO];
-      [window_ setToolbar:toolbar];
-    } else {
-      [window_ enableWindowButtonsOffset];
-      [window_ setWindowButtonsOffset:NSMakePoint(12, 10)];
-    }
+    base::scoped_nsobject<NSToolbar> toolbar(
+        [[NSToolbar alloc] initWithIdentifier:@"titlebarStylingToolbar"]);
+    [toolbar setShowsBaselineSeparator:NO];
+    [window_ setToolbar:toolbar];
   }
 
   // Resize to content bounds.
@@ -445,9 +435,8 @@ NativeWindowMac::NativeWindowMac(const mate::Dictionary& options,
   SetContentView(new views::View());
 
   // Make sure the bottom corner is rounded for non-modal windows:
-  // http://crbug.com/396264. But do not enable it on OS X 10.9 for transparent
-  // window, otherwise a semi-transparent frame would show.
-  if (!(transparent() && base::mac::IsOS10_9()) && !is_modal()) {
+  // http://crbug.com/396264.
+  if (!is_modal()) {
     base::scoped_nsobject<CALayer> background_layer([[CALayer alloc] init]);
     [background_layer
         setAutoresizingMask:kCALayerWidthSizable | kCALayerHeightSizable];
@@ -479,11 +468,6 @@ NativeWindowMac::NativeWindowMac(const mate::Dictionary& options,
       [[window_ contentView] addSubview:buttons_view_];
     } else {
       if (title_bar_style_ != NORMAL) {
-        if (base::mac::IsOS10_9()) {
-          ShowWindowButton(NSWindowZoomButton);
-          ShowWindowButton(NSWindowMiniaturizeButton);
-          ShowWindowButton(NSWindowCloseButton);
-        }
         return;
       }
 
@@ -858,17 +842,11 @@ void NativeWindowMac::Invalidate() {
 }
 
 void NativeWindowMac::SetTitle(const std::string& title) {
-  // For macOS <= 10.9, the setTitleVisibility API is not available, we have
-  // to avoid calling setTitle for frameless window.
-  if (!base::mac::IsAtLeastOS10_10() && (transparent() || !has_frame()))
-    return;
-
   [window_ setTitle:base::SysUTF8ToNSString(title)];
 }
 
 std::string NativeWindowMac::GetTitle() {
   return base::SysNSStringToUTF8([window_ title]);
-  ;
 }
 
 void NativeWindowMac::FlashFrame(bool flash) {
@@ -1178,86 +1156,83 @@ bool NativeWindowMac::AddTabbedWindow(NativeWindow* window) {
 }
 
 void NativeWindowMac::SetVibrancy(const std::string& type) {
-  if (@available(macOS 10.10, *)) {
-    NSView* vibrant_view = [window_ vibrantView];
-
-    if (type.empty()) {
-      if (background_color_before_vibrancy_) {
-        [window_ setBackgroundColor:background_color_before_vibrancy_];
-        [window_ setTitlebarAppearsTransparent:transparency_before_vibrancy_];
-      }
-      if (vibrant_view == nil)
-        return;
-
-      [vibrant_view removeFromSuperview];
-      [window_ setVibrantView:nil];
-      ui::GpuSwitchingManager::SetTransparent(transparent());
+  NSView* vibrant_view = [window_ vibrantView];
 
+  if (type.empty()) {
+    if (background_color_before_vibrancy_) {
+      [window_ setBackgroundColor:background_color_before_vibrancy_];
+      [window_ setTitlebarAppearsTransparent:transparency_before_vibrancy_];
+    }
+    if (vibrant_view == nil)
       return;
-    }
 
-    background_color_before_vibrancy_.reset([[window_ backgroundColor] retain]);
-    transparency_before_vibrancy_ = [window_ titlebarAppearsTransparent];
-    ui::GpuSwitchingManager::SetTransparent(true);
+    [vibrant_view removeFromSuperview];
+    [window_ setVibrantView:nil];
+    ui::GpuSwitchingManager::SetTransparent(transparent());
 
-    if (title_bar_style_ != NORMAL) {
-      [window_ setTitlebarAppearsTransparent:YES];
-      [window_ setBackgroundColor:[NSColor clearColor]];
-    }
-
-    NSVisualEffectView* effect_view = (NSVisualEffectView*)vibrant_view;
-    if (effect_view == nil) {
-      effect_view = [[[NSVisualEffectView alloc]
-          initWithFrame:[[window_ contentView] bounds]] autorelease];
-      [window_ setVibrantView:(NSView*)effect_view];
-
-      [effect_view
-          setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
-      [effect_view setBlendingMode:NSVisualEffectBlendingModeBehindWindow];
-      [effect_view setState:NSVisualEffectStateActive];
-      [[window_ contentView] addSubview:effect_view
-                             positioned:NSWindowBelow
-                             relativeTo:nil];
-    }
-
-    NSVisualEffectMaterial vibrancyType = NSVisualEffectMaterialLight;
-
-    if (type == "appearance-based") {
-      vibrancyType = NSVisualEffectMaterialAppearanceBased;
-    } else if (type == "light") {
-      vibrancyType = NSVisualEffectMaterialLight;
-    } else if (type == "dark") {
-      vibrancyType = NSVisualEffectMaterialDark;
-    } else if (type == "titlebar") {
-      vibrancyType = NSVisualEffectMaterialTitlebar;
-    }
-
-    if (@available(macOS 10.11, *)) {
-      // TODO(kevinsawicki): Use NSVisualEffectMaterial* constants directly once
-      // they are available in the minimum SDK version
-      if (type == "selection") {
-        // NSVisualEffectMaterialSelection
-        vibrancyType = static_cast<NSVisualEffectMaterial>(4);
-      } else if (type == "menu") {
-        // NSVisualEffectMaterialMenu
-        vibrancyType = static_cast<NSVisualEffectMaterial>(5);
-      } else if (type == "popover") {
-        // NSVisualEffectMaterialPopover
-        vibrancyType = static_cast<NSVisualEffectMaterial>(6);
-      } else if (type == "sidebar") {
-        // NSVisualEffectMaterialSidebar
-        vibrancyType = static_cast<NSVisualEffectMaterial>(7);
-      } else if (type == "medium-light") {
-        // NSVisualEffectMaterialMediumLight
-        vibrancyType = static_cast<NSVisualEffectMaterial>(8);
-      } else if (type == "ultra-dark") {
-        // NSVisualEffectMaterialUltraDark
-        vibrancyType = static_cast<NSVisualEffectMaterial>(9);
-      }
-    }
-
-    [effect_view setMaterial:vibrancyType];
+    return;
   }
+
+  background_color_before_vibrancy_.reset([[window_ backgroundColor] retain]);
+  transparency_before_vibrancy_ = [window_ titlebarAppearsTransparent];
+  ui::GpuSwitchingManager::SetTransparent(true);
+
+  if (title_bar_style_ != NORMAL) {
+    [window_ setTitlebarAppearsTransparent:YES];
+    [window_ setBackgroundColor:[NSColor clearColor]];
+  }
+
+  NSVisualEffectView* effect_view = (NSVisualEffectView*)vibrant_view;
+  if (effect_view == nil) {
+    effect_view = [[[NSVisualEffectView alloc]
+        initWithFrame:[[window_ contentView] bounds]] autorelease];
+    [window_ setVibrantView:(NSView*)effect_view];
+
+    [effect_view setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+    [effect_view setBlendingMode:NSVisualEffectBlendingModeBehindWindow];
+    [effect_view setState:NSVisualEffectStateActive];
+    [[window_ contentView] addSubview:effect_view
+                           positioned:NSWindowBelow
+                           relativeTo:nil];
+  }
+
+  NSVisualEffectMaterial vibrancyType = NSVisualEffectMaterialLight;
+
+  if (type == "appearance-based") {
+    vibrancyType = NSVisualEffectMaterialAppearanceBased;
+  } else if (type == "light") {
+    vibrancyType = NSVisualEffectMaterialLight;
+  } else if (type == "dark") {
+    vibrancyType = NSVisualEffectMaterialDark;
+  } else if (type == "titlebar") {
+    vibrancyType = NSVisualEffectMaterialTitlebar;
+  }
+
+  if (@available(macOS 10.11, *)) {
+    // TODO(kevinsawicki): Use NSVisualEffectMaterial* constants directly once
+    // they are available in the minimum SDK version
+    if (type == "selection") {
+      // NSVisualEffectMaterialSelection
+      vibrancyType = static_cast<NSVisualEffectMaterial>(4);
+    } else if (type == "menu") {
+      // NSVisualEffectMaterialMenu
+      vibrancyType = static_cast<NSVisualEffectMaterial>(5);
+    } else if (type == "popover") {
+      // NSVisualEffectMaterialPopover
+      vibrancyType = static_cast<NSVisualEffectMaterial>(6);
+    } else if (type == "sidebar") {
+      // NSVisualEffectMaterialSidebar
+      vibrancyType = static_cast<NSVisualEffectMaterial>(7);
+    } else if (type == "medium-light") {
+      // NSVisualEffectMaterialMediumLight
+      vibrancyType = static_cast<NSVisualEffectMaterial>(8);
+    } else if (type == "ultra-dark") {
+      // NSVisualEffectMaterialUltraDark
+      vibrancyType = static_cast<NSVisualEffectMaterial>(9);
+    }
+  }
+
+  [effect_view setMaterial:vibrancyType];
 }
 
 void NativeWindowMac::SetTouchBar(
@@ -1341,11 +1316,6 @@ void NativeWindowMac::InternalSetParentWindow(NativeWindow* parent,
     [parent->GetNativeWindow() addChildWindow:window_ ordered:NSWindowAbove];
 }
 
-void NativeWindowMac::ShowWindowButton(NSWindowButton button) {
-  auto view = [window_ standardWindowButton:button];
-  [view.superview addSubview:view positioned:NSWindowAbove relativeTo:nil];
-}
-
 void NativeWindowMac::SetForwardMouseMessages(bool forward) {
   [window_ setAcceptsMouseMovedEvents:forward];
 }
diff --git a/atom/browser/ui/cocoa/atom_ns_window.h b/atom/browser/ui/cocoa/atom_ns_window.h
index 7fd8f2a9a2a2..ee13e7137ce0 100644
--- a/atom/browser/ui/cocoa/atom_ns_window.h
+++ b/atom/browser/ui/cocoa/atom_ns_window.h
@@ -29,19 +29,16 @@ class ScopedDisableResize {
 @interface AtomNSWindow : NativeWidgetMacNSWindow {
  @private
   atom::NativeWindowMac* shell_;
-  CGFloat windowButtonsInterButtonSpacing_;
 }
 @property BOOL acceptsFirstMouse;
 @property BOOL enableLargerThanScreen;
 @property BOOL disableAutoHideCursor;
 @property BOOL disableKeyOrMainWindow;
-@property NSPoint windowButtonsOffset;
 @property(nonatomic, retain) NSView* vibrantView;
 - (id)initWithShell:(atom::NativeWindowMac*)shell
           styleMask:(NSUInteger)styleMask;
 - (atom::NativeWindowMac*)shell;
 - (NSRect)originalContentRectForFrameRect:(NSRect)frameRect;
-- (void)enableWindowButtonsOffset;
 - (void)toggleFullScreenMode:(id)sender;
 @end
 
diff --git a/atom/browser/ui/cocoa/atom_ns_window.mm b/atom/browser/ui/cocoa/atom_ns_window.mm
index 56ed5dc2319c..9087f6234338 100644
--- a/atom/browser/ui/cocoa/atom_ns_window.mm
+++ b/atom/browser/ui/cocoa/atom_ns_window.mm
@@ -21,7 +21,6 @@ bool ScopedDisableResize::disable_resize_ = false;
 @synthesize enableLargerThanScreen;
 @synthesize disableAutoHideCursor;
 @synthesize disableKeyOrMainWindow;
-@synthesize windowButtonsOffset;
 @synthesize vibrantView;
 
 - (id)initWithShell:(atom::NativeWindowMac*)shell
@@ -117,78 +116,6 @@ bool ScopedDisableResize::disable_resize_ = false;
   return !self.disableKeyOrMainWindow;
 }
 
-- (void)enableWindowButtonsOffset {
-  auto closeButton = [self standardWindowButton:NSWindowCloseButton];
-  auto miniaturizeButton =
-      [self standardWindowButton:NSWindowMiniaturizeButton];
-  auto zoomButton = [self standardWindowButton:NSWindowZoomButton];
-
-  [closeButton setPostsFrameChangedNotifications:YES];
-  [miniaturizeButton setPostsFrameChangedNotifications:YES];
-  [zoomButton setPostsFrameChangedNotifications:YES];
-
-  windowButtonsInterButtonSpacing_ =
-      NSMinX([miniaturizeButton frame]) - NSMaxX([closeButton frame]);
-
-  auto center = [NSNotificationCenter defaultCenter];
-
-  [center addObserver:self
-             selector:@selector(adjustCloseButton:)
-                 name:NSViewFrameDidChangeNotification
-               object:closeButton];
-
-  [center addObserver:self
-             selector:@selector(adjustMiniaturizeButton:)
-                 name:NSViewFrameDidChangeNotification
-               object:miniaturizeButton];
-
-  [center addObserver:self
-             selector:@selector(adjustZoomButton:)
-                 name:NSViewFrameDidChangeNotification
-               object:zoomButton];
-}
-
-- (void)adjustCloseButton:(NSNotification*)notification {
-  [self adjustButton:[notification object] ofKind:NSWindowCloseButton];
-}
-
-- (void)adjustMiniaturizeButton:(NSNotification*)notification {
-  [self adjustButton:[notification object] ofKind:NSWindowMiniaturizeButton];
-}
-
-- (void)adjustZoomButton:(NSNotification*)notification {
-  [self adjustButton:[notification object] ofKind:NSWindowZoomButton];
-}
-
-- (void)adjustButton:(NSButton*)button ofKind:(NSWindowButton)kind {
-  NSRect buttonFrame = [button frame];
-  NSRect frameViewBounds = [[self frameView] bounds];
-  NSPoint offset = self.windowButtonsOffset;
-
-  buttonFrame.origin = NSMakePoint(
-      offset.x, (NSHeight(frameViewBounds) - NSHeight(buttonFrame) - offset.y));
-
-  switch (kind) {
-    case NSWindowZoomButton:
-      buttonFrame.origin.x += NSWidth(
-          [[self standardWindowButton:NSWindowMiniaturizeButton] frame]);
-      buttonFrame.origin.x += windowButtonsInterButtonSpacing_;
-      // fallthrough
-    case NSWindowMiniaturizeButton:
-      buttonFrame.origin.x +=
-          NSWidth([[self standardWindowButton:NSWindowCloseButton] frame]);
-      buttonFrame.origin.x += windowButtonsInterButtonSpacing_;
-      // fallthrough
-    default:
-      break;
-  }
-
-  BOOL didPost = [button postsBoundsChangedNotifications];
-  [button setPostsFrameChangedNotifications:NO];
-  [button setFrame:buttonFrame];
-  [button setPostsFrameChangedNotifications:didPost];
-}
-
 - (NSView*)frameView {
   return [[self contentView] superview];
 }
diff --git a/atom/browser/ui/cocoa/atom_ns_window_delegate.mm b/atom/browser/ui/cocoa/atom_ns_window_delegate.mm
index 78bfe1fcd7b5..97a441efdfad 100644
--- a/atom/browser/ui/cocoa/atom_ns_window_delegate.mm
+++ b/atom/browser/ui/cocoa/atom_ns_window_delegate.mm
@@ -168,60 +168,54 @@
   shell_->SetResizable(true);
   // Hide the native toolbar before entering fullscreen, so there is no visual
   // artifacts.
-  if (@available(macOS 10.10, *)) {
-    if (shell_->title_bar_style() == atom::NativeWindowMac::HIDDEN_INSET) {
-      NSWindow* window = shell_->GetNativeWindow();
-      [window setToolbar:nil];
-    }
+  if (shell_->title_bar_style() == atom::NativeWindowMac::HIDDEN_INSET) {
+    NSWindow* window = shell_->GetNativeWindow();
+    [window setToolbar:nil];
   }
 }
 
 - (void)windowDidEnterFullScreen:(NSNotification*)notification {
   shell_->NotifyWindowEnterFullScreen();
 
-  if (@available(macOS 10.10, *)) {
-    // For frameless window we don't show set title for normal mode since the
-    // titlebar is expected to be empty, but after entering fullscreen mode we
-    // have to set one, because title bar is visible here.
-    NSWindow* window = shell_->GetNativeWindow();
-    if ((shell_->transparent() || !shell_->has_frame()) &&
-        // FIXME(zcbenz): Showing titlebar for hiddenInset window is weird under
-        // fullscreen mode.
-        // Show title if fullscreen_window_title flag is set
-        (shell_->title_bar_style() != atom::NativeWindowMac::HIDDEN_INSET ||
-         shell_->fullscreen_window_title())) {
-      [window setTitleVisibility:NSWindowTitleVisible];
-    }
+  // For frameless window we don't show set title for normal mode since the
+  // titlebar is expected to be empty, but after entering fullscreen mode we
+  // have to set one, because title bar is visible here.
+  NSWindow* window = shell_->GetNativeWindow();
+  if ((shell_->transparent() || !shell_->has_frame()) &&
+      // FIXME(zcbenz): Showing titlebar for hiddenInset window is weird under
+      // fullscreen mode.
+      // Show title if fullscreen_window_title flag is set
+      (shell_->title_bar_style() != atom::NativeWindowMac::HIDDEN_INSET ||
+       shell_->fullscreen_window_title())) {
+    [window setTitleVisibility:NSWindowTitleVisible];
+  }
 
-    // Restore the native toolbar immediately after entering fullscreen, if we
-    // do this before leaving fullscreen, traffic light buttons will be jumping.
-    if (shell_->title_bar_style() == atom::NativeWindowMac::HIDDEN_INSET) {
-      base::scoped_nsobject<NSToolbar> toolbar(
-          [[NSToolbar alloc] initWithIdentifier:@"titlebarStylingToolbar"]);
-      [toolbar setShowsBaselineSeparator:NO];
-      [window setToolbar:toolbar];
+  // Restore the native toolbar immediately after entering fullscreen, if we
+  // do this before leaving fullscreen, traffic light buttons will be jumping.
+  if (shell_->title_bar_style() == atom::NativeWindowMac::HIDDEN_INSET) {
+    base::scoped_nsobject<NSToolbar> toolbar(
+        [[NSToolbar alloc] initWithIdentifier:@"titlebarStylingToolbar"]);
+    [toolbar setShowsBaselineSeparator:NO];
+    [window setToolbar:toolbar];
 
-      // Set window style to hide the toolbar, otherwise the toolbar will show
-      // in fullscreen mode.
-      shell_->SetStyleMask(true, NSFullSizeContentViewWindowMask);
-    }
+    // Set window style to hide the toolbar, otherwise the toolbar will show
+    // in fullscreen mode.
+    shell_->SetStyleMask(true, NSFullSizeContentViewWindowMask);
   }
 }
 
 - (void)windowWillExitFullScreen:(NSNotification*)notification {
-  if (@available(macOS 10.10, *)) {
-    // Restore the titlebar visibility.
-    NSWindow* window = shell_->GetNativeWindow();
-    if ((shell_->transparent() || !shell_->has_frame()) &&
-        (shell_->title_bar_style() != atom::NativeWindowMac::HIDDEN_INSET ||
-         shell_->fullscreen_window_title())) {
-      [window setTitleVisibility:NSWindowTitleHidden];
-    }
+  // Restore the titlebar visibility.
+  NSWindow* window = shell_->GetNativeWindow();
+  if ((shell_->transparent() || !shell_->has_frame()) &&
+      (shell_->title_bar_style() != atom::NativeWindowMac::HIDDEN_INSET ||
+       shell_->fullscreen_window_title())) {
+    [window setTitleVisibility:NSWindowTitleHidden];
+  }
 
-    // Turn off the style for toolbar.
-    if (shell_->title_bar_style() == atom::NativeWindowMac::HIDDEN_INSET) {
-      shell_->SetStyleMask(false, NSFullSizeContentViewWindowMask);
-    }
+  // Turn off the style for toolbar.
+  if (shell_->title_bar_style() == atom::NativeWindowMac::HIDDEN_INSET) {
+    shell_->SetStyleMask(false, NSFullSizeContentViewWindowMask);
   }
 }
 
diff --git a/brightray/browser/mac/cocoa_notification.h b/brightray/browser/mac/cocoa_notification.h
index 066528ee490b..41f6d4b5a423 100644
--- a/brightray/browser/mac/cocoa_notification.h
+++ b/brightray/browser/mac/cocoa_notification.h
@@ -29,8 +29,7 @@ class CocoaNotification : public Notification {
   void NotificationDisplayed();
   void NotificationReplied(const std::string& reply);
   void NotificationActivated();
-  void NotificationActivated(NSUserNotificationAction* action)
-    API_AVAILABLE(macosx(10.10));
+  void NotificationActivated(NSUserNotificationAction* action);
 
   NSUserNotification* notification() const { return notification_; }
 
diff --git a/brightray/browser/mac/cocoa_notification.mm b/brightray/browser/mac/cocoa_notification.mm
index 6b576497d41a..1f51d64e99f2 100644
--- a/brightray/browser/mac/cocoa_notification.mm
+++ b/brightray/browser/mac/cocoa_notification.mm
@@ -72,24 +72,18 @@ void CocoaNotification::Show(const NotificationOptions& options) {
         // All of the rest are appended to the list of additional actions
         NSString* actionIdentifier =
             [NSString stringWithFormat:@"%@Action%d", identifier, i];
-        if (@available(macOS 10.10, *)) {
-          NSUserNotificationAction* notificationAction =
-              [NSUserNotificationAction
-                  actionWithIdentifier:actionIdentifier
-                                 title:base::SysUTF16ToNSString(action.text)];
-          [additionalActions addObject:notificationAction];
-          additional_action_indices_.insert(
-              std::make_pair(base::SysNSStringToUTF8(actionIdentifier), i));
-        }
+        NSUserNotificationAction* notificationAction = [NSUserNotificationAction
+            actionWithIdentifier:actionIdentifier
+                           title:base::SysUTF16ToNSString(action.text)];
+        [additionalActions addObject:notificationAction];
+        additional_action_indices_.insert(
+            std::make_pair(base::SysNSStringToUTF8(actionIdentifier), i));
       }
     }
     i++;
   }
-  if ([additionalActions count] > 0 &&
-      [notification_ respondsToSelector:@selector(setAdditionalActions:)]) {
-    if (@available(macOS 10.10, *)) {
-      [notification_ setAdditionalActions:additionalActions];
-    }
+  if ([additionalActions count] > 0) {
+    [notification_ setAdditionalActions:additionalActions];
   }
 
   if (options.has_reply) {
diff --git a/brightray/browser/mac/notification_center_delegate.mm b/brightray/browser/mac/notification_center_delegate.mm
index 7ae24b8979b4..ea4c53bfa9a8 100644
--- a/brightray/browser/mac/notification_center_delegate.mm
+++ b/brightray/browser/mac/notification_center_delegate.mm
@@ -48,12 +48,9 @@
                NSUserNotificationActivationTypeReplied) {
       notification->NotificationReplied([notif.response.string UTF8String]);
     } else {
-      if (@available(macOS 10.10, *)) {
-        if (notif.activationType ==
-            NSUserNotificationActivationTypeAdditionalActionClicked) {
-          notification->NotificationActivated(
-              [notif additionalActivationAction]);
-        }
+      if (notif.activationType ==
+          NSUserNotificationActivationTypeAdditionalActionClicked) {
+        notification->NotificationActivated([notif additionalActivationAction]);
       }
     }
   }
diff --git a/docs/api/frameless-window.md b/docs/api/frameless-window.md
index 46e496407a8d..868f0621e73c 100644
--- a/docs/api/frameless-window.md
+++ b/docs/api/frameless-window.md
@@ -21,11 +21,10 @@ win.show()
 
 ### Alternatives on macOS
 
-On macOS 10.9 Mavericks and newer, there's an alternative way to specify
-a chromeless window. Instead of setting `frame` to `false` which disables
-both the titlebar and window controls, you may want to have the title bar
-hidden and your content extend to the full window size, yet still preserve
-the window controls ("traffic lights") for standard window actions.
+There's an alternative way to specify a chromeless window.
+Instead of setting `frame` to `false` which disables both the titlebar and window controls,
+you may want to have the title bar hidden and your content extend to the full window size,
+yet still preserve the window controls ("traffic lights") for standard window actions.
 You can do so by specifying the `titleBarStyle` option:
 
 #### `hidden`
diff --git a/docs/tutorial/development-environment.md b/docs/tutorial/development-environment.md
index 3a5b956208e5..741d6c35560c 100644
--- a/docs/tutorial/development-environment.md
+++ b/docs/tutorial/development-environment.md
@@ -7,7 +7,7 @@ rudimentary understanding of your operating system's command line client.
 
 ## Setting up macOS
 
-> Electron supports Mac OS X 10.9 (and all versions named macOS) and up. Apple
+> Electron supports OS X Yosemite (version 10.10) and up. Apple
 does not allow running macOS in virtual machines unless the host computer is
 already an Apple computer, so if you find yourself in need of a Mac, consider
 using a cloud service that rents access to Macs (like [MacInCloud][macincloud]
diff --git a/docs/tutorial/support.md b/docs/tutorial/support.md
index bdb3b8678485..db8c496cd3d2 100644
--- a/docs/tutorial/support.md
+++ b/docs/tutorial/support.md
@@ -61,7 +61,7 @@ Following platforms are supported by Electron:
 ### macOS
 
 Only 64bit binaries are provided for macOS, and the minimum macOS version
-supported is macOS 10.9.
+supported is OS X Yosemite (version 10.10).
 
 ### Windows
 
@@ -79,7 +79,7 @@ Ubuntu 12.04, the `armv7l` binary is built against ARM v7 with hard-float ABI an
 NEON for Debian Wheezy.
 
 [Until the release of Electron 2.0][arm-breaking-change], Electron will also
-continue to release the `armv7l` binary with a simple `arm` suffix. Both binaries 
+continue to release the `armv7l` binary with a simple `arm` suffix. Both binaries
 are identical.
 
 Whether the prebuilt binary can run on a distribution depends on whether the