diff --git a/Telegram/SourceFiles/base/base_pch.h b/Telegram/SourceFiles/base/base_pch.h
index 6fd4889593..91cfe95ee1 100644
--- a/Telegram/SourceFiles/base/base_pch.h
+++ b/Telegram/SourceFiles/base/base_pch.h
@@ -14,10 +14,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtCore/QThread>
 #include <QtCore/QCoreApplication>
 
-#if QT_VERSION < QT_VERSION_CHECK(5, 5, 0)
-#define OS_MAC_OLD
-#endif // QT_VERSION < 5.5.0
-
 #include <crl/crl.h>
 #include <rpl/rpl.h>
 
diff --git a/Telegram/SourceFiles/base/basic_types.h b/Telegram/SourceFiles/base/basic_types.h
index 08c6218fbd..c32a4b4487 100644
--- a/Telegram/SourceFiles/base/basic_types.h
+++ b/Telegram/SourceFiles/base/basic_types.h
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/functors.h"
 
 #include <QtGlobal>
+#include <QtCore/QByteArray>
 
 #include <string>
 #include <exception>
@@ -50,7 +51,7 @@ using TimeId = int32;
 
 // Define specializations for QByteArray for Qt 5.3.2, because
 // QByteArray in Qt 5.3.2 doesn't declare "pointer" subtype.
-#ifdef OS_MAC_OLD
+#if QT_VERSION < QT_VERSION_CHECK(5, 5, 0)
 namespace gsl {
 
 template <>
diff --git a/Telegram/SourceFiles/export/export_pch.h b/Telegram/SourceFiles/export/export_pch.h
index 475eb75d6b..8c420524a2 100644
--- a/Telegram/SourceFiles/export/export_pch.h
+++ b/Telegram/SourceFiles/export/export_pch.h
@@ -17,10 +17,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtCore/QReadWriteLock>
 #include <QtCore/QRegularExpression>
 
-#if QT_VERSION < QT_VERSION_CHECK(5, 5, 0)
-#define OS_MAC_OLD
-#endif // QT_VERSION < 5.5.0
-
 #include <crl/crl.h>
 #include <rpl/rpl.h>
 
diff --git a/Telegram/SourceFiles/stdafx.h b/Telegram/SourceFiles/stdafx.h
index 77be48192b..f19903e502 100644
--- a/Telegram/SourceFiles/stdafx.h
+++ b/Telegram/SourceFiles/stdafx.h
@@ -36,10 +36,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma warning(pop)
 #endif // __clang__ || _MSC_VER >= 1914
 
-#if QT_VERSION < QT_VERSION_CHECK(5, 5, 0)
-#define OS_MAC_OLD
-#endif // QT_VERSION < 5.5.0
-
 #ifdef OS_MAC_STORE
 #define MAC_USE_BREAKPAD
 #endif // OS_MAC_STORE
diff --git a/Telegram/SourceFiles/storage/storage_pch.h b/Telegram/SourceFiles/storage/storage_pch.h
index 11e41c6cf0..64d635c3da 100644
--- a/Telegram/SourceFiles/storage/storage_pch.h
+++ b/Telegram/SourceFiles/storage/storage_pch.h
@@ -12,10 +12,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtCore/QByteArray>
 #include <QtCore/QString>
 
-#if QT_VERSION < QT_VERSION_CHECK(5, 5, 0)
-#define OS_MAC_OLD
-#endif // QT_VERSION < 5.5.0
-
 #include <crl/crl.h>
 #include <rpl/rpl.h>
 
diff --git a/Telegram/gyp/telegram_mac.gypi b/Telegram/gyp/telegram_mac.gypi
index 0195ddb0b4..68591c439f 100644
--- a/Telegram/gyp/telegram_mac.gypi
+++ b/Telegram/gyp/telegram_mac.gypi
@@ -37,6 +37,9 @@
       },
     },
   }], [ 'build_macold', {
+    'defines': [
+      'OS_MAC_OLD',
+    ],
     'xcode_settings': {
       'OTHER_CPLUSPLUSFLAGS': [ '-nostdinc++' ],
       'OTHER_LDFLAGS': [