VFX Platform 2027: macOS Minimum Deployment Target

[Jean-Francois Panisset]

Hi everyone,

Currently the draft 2027 version of the VFX Platform calls for:

macOS Minimum Deployment Target: 15.0
Qt: 6.8.x

The current open source version of Qt 6.8.x is 6.8.4, and when trying
to build on macOS with -DCMAKE_OSX_DEPLOYMENT_TARGET=15.0 the build
fails for the Cocoa QPA (and eventually for qtwebengine) with:

---
CMake Error at qtbase/src/plugins/platforms/cocoa/CMakeLists.txt:83 (message):
QCocoaScreen uses APIs removed in 15.0. Please specify a

CMAKE_OSX_DEPLOYMENT_TARGET of 14.0 or lower
---

Although it looks like this issue was recently addressed in the
upcoming 6.12.0 LTS release, that release will be coming out too late
in the VFX Platform 2027 cycle to allow time to integrate a large Qt
version bump, and backporting those fixes into 6.8.x would be tricky
(in particular there are significant related changes to qtwebengine).

We are considering reverting the macOS Minimum Deployment Target to
14.0 (which is what was specified for VFX Platform 2026). An
application which wanted to conditionally access new APIs in 15.0
could still build against the 15.0 SDK and conditionally check for
availability at run time.

Let us know if this change seems appropriate.

Jean-Francois Panisset