Platforms must synchronize captioning settings across devices, unless overridden by the user. This ensures that accessibility preferences, once set, remain consistent across different platforms and devices. However, apps and websites with account-based Closed Captioning styles and synchronized settings must use the system-level settings and styles until overridden by the user on each new device.
1.1.3-A
Platforms must use the default, system-level Closed Captioning settings and styles if a user has not overridden them or signs out of their platform account. The currently selected, platform-based, Closed Captioning state (on or off) must be respected until the user changes it. The default, system-level style must render captions without customizations as set by the CC content providers until the user changes them.
1.1.3-B
Platforms, apps, and websites with account-based synchronizations must show styles created on other devices, allow selection of synchronized styles, and offer saving customized styles as new, synchronized styles.
1.1.3-C
Once overridden, the Closed Captioning style must remain persistent on relaunch, restart, or reboot of the platform, app, or website unless the user has changed the system-level style or signed out of their account. Developers must not use cookies as the only storage method for Closed Captioning style data; cookies are not persistent.
1.1.3-D
Apps and websites must detect system-level Closed Captioning style changes and use the updated system-level style until overridden by the user within the app or website. Apps and websites must also use the system-level Closed Captioning style if a user signs out of their account.