diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 8e57a111..6f92d617 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -13,10 +13,9 @@ jobs:
     strategy:
       matrix:
         os:
-          # wrong use of AU MIDIPacket
-          # - macos-12
-          # - macos-13
-          # - macos-14
+          - macos-13
+          - macos-14
+          - macos-15
           # webgui failure
           # - ubuntu-20.04
           - ubuntu-22.04
diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index 4202a693..5bdbbced 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -42,11 +42,11 @@ jobs:
           suffix: _24_04
           target: ${{ matrix.target }}
 
-  macos-12:
+  macos-13:
     strategy:
       matrix:
         target: [macos-intel, macos-universal, macos-10.15]
-    runs-on: macos-12
+    runs-on: macos-13
     steps:
       - uses: actions/checkout@v4
         with:
@@ -54,14 +54,14 @@ jobs:
       - uses: distrho/dpf-cmake-action@v1
         with:
           dpf_path: .
-          suffix: _12
+          suffix: _13
           target: ${{ matrix.target }}
 
-  macos-13:
+  macos-14:
     strategy:
       matrix:
         target: [macos-intel, macos-universal, macos-10.15]
-    runs-on: macos-13
+    runs-on: macos-14
     steps:
       - uses: actions/checkout@v4
         with:
@@ -69,14 +69,14 @@ jobs:
       - uses: distrho/dpf-cmake-action@v1
         with:
           dpf_path: .
-          suffix: _13
+          suffix: _14
           target: ${{ matrix.target }}
 
-  macos-14:
+  macos-15:
     strategy:
       matrix:
         target: [macos-intel, macos-universal, macos-10.15]
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
         with:
@@ -84,7 +84,7 @@ jobs:
       - uses: distrho/dpf-cmake-action@v1
         with:
           dpf_path: .
-          suffix: _14
+          suffix: _15
           target: ${{ matrix.target }}
 
   cmake_win32:
diff --git a/.github/workflows/example-plugins.yml b/.github/workflows/example-plugins.yml
index 8ac77fcc..86bd43e0 100644
--- a/.github/workflows/example-plugins.yml
+++ b/.github/workflows/example-plugins.yml
@@ -39,11 +39,11 @@ jobs:
           suffix: _24_04
           target: ${{ matrix.target }}
 
-  macos-12:
+  macos-13:
     strategy:
       matrix:
         target: [macos-intel, macos-universal, macos-10.15]
-    runs-on: macos-12
+    runs-on: macos-13
     steps:
       - uses: actions/checkout@v4
         with:
@@ -51,14 +51,14 @@ jobs:
       - uses: distrho/dpf-makefile-action@v1
         with:
           dpf_path: .
-          suffix: _12
+          suffix: _13
           target: ${{ matrix.target }}
 
-  macos-13:
+  macos-14:
     strategy:
       matrix:
         target: [macos-intel, macos-universal, macos-10.15]
-    runs-on: macos-13
+    runs-on: macos-14
     steps:
       - uses: actions/checkout@v4
         with:
@@ -66,14 +66,14 @@ jobs:
       - uses: distrho/dpf-makefile-action@v1
         with:
           dpf_path: .
-          suffix: _13
+          suffix: _14
           target: ${{ matrix.target }}
 
-  macos-14:
+  macos-15:
     strategy:
       matrix:
         target: [macos-intel, macos-universal, macos-10.15]
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
         with:
@@ -81,5 +81,5 @@ jobs:
       - uses: distrho/dpf-makefile-action@v1
         with:
           dpf_path: .
-          suffix: _14
+          suffix: _15
           target: ${{ matrix.target }}
diff --git a/distrho/src/DistrhoPluginAU.cpp b/distrho/src/DistrhoPluginAU.cpp
index 863a4744..0c2b3de4 100644
--- a/distrho/src/DistrhoPluginAU.cpp
+++ b/distrho/src/DistrhoPluginAU.cpp
@@ -277,9 +277,12 @@ typedef std::vector<PropertyListener> PropertyListeners;
 typedef std::vector<RenderListener> RenderListeners;
 
 #if DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
+static_assert(sizeof(MIDIPacket) == sizeof(MIDITimeStamp) + sizeof(UInt16), "data size correct");
+static_assert(sizeof(MIDIPacketList) == sizeof(UInt32), "data size correct");
+
 // useful definitions
-static constexpr const uint32_t kMIDIPacketNonDataSize = sizeof(MIDIPacket) - sizeof(MIDIPacket::data);
-static constexpr const uint32_t kMIDIPacketListNonDataSize = sizeof(MIDIPacketList) - sizeof(MIDIPacketList::packet);
+static constexpr const uint32_t kMIDIPacketNonDataSize = sizeof(MIDIPacket); // - sizeof(MIDIPacket::data)
+static constexpr const uint32_t kMIDIPacketListNonDataSize = sizeof(MIDIPacketList); // - sizeof(MIDIPacketList::packet)
 
 // size of data used for midi events
 static constexpr const uint32_t kMIDIPacketListMaxDataSize = kMIDIPacketNonDataSize * kMaxMidiEvents