Qt 6.8

Apply the C++23 baseline prompt first. These rules target native applications built with Qt 6.8 and were checked against Qt 6.8.8. Apply optional-module rules when those modules are shipped.

Release scope and patch level

• Get Qt 6.8 LTS patch releases through the commercial LTS distribution and verify the module versions actually deployed: Qt ships 6.8 patch releases after 6.8.3 only there, the public open-source 6.8 line ended at 6.8.3, and a 6.8.3 installation without Qt's published security patches is not equivalent. Account separately for Qt WebEngine, whose LTS source remains available under its default licenses.
• Run the newest Qt 6.8 LTS patch release, or apply every relevant official patch that Qt publishes with its advisories to a retained build, because Qt fixes the 6.8 line through commercial patch releases and per-advisory source patches; the LTS support window through 2029-10-08 doesn't make an old patch safe.
• Match the Qt 6.8 supported OS, compiler, architecture, and runtime-library combinations, including each module's exceptions. Qt generally requires C++17 and WebEngine requires a C++20-capable compiler; use a C++23-capable toolchain for the application and satisfy each module's additional requirements.
• Track Qt WebEngine's Chromium base and security-backport level separately: 6.8.8 uses Chromium 134.0.6998.208 with security fixes through 148.0.7778.215. Regression-test its rebase when moving from 6.8.7's Chromium 130 build.

Object lifetime and threads

• Use the QObject::connect(sender, signal, context, functor) overload for lambdas that