Add "Compatible up to" plugin header

[azaozz]

This idea has been floating around for a while. It would be really helpful for plugins to be able to set a maximum supported WP version in addition to the minimum/required version. That would allow the plugins to ensure they are being updated on time and will not cause errors in future versions of WordPress.

Thinking that an optional Compatible up to header in the plugin's file (same as Requires at least and Requires PHP) would serve that purpose well. Then in core that header can be checked and the plugin not loaded if WordPress is newer, similarly to how the Requires PHP check works.

On the plugins directory side the Compatible up to header may eventually be used to sent a warning message when installing plugins through wp-admin. Perhaps like "This plugin is too old and is not compatible with your version of WordPress" instead of the "This plugin has not been tested with your version of WordPress" when the header is present.

[swissspidy]

IMHO the cases this is useful for is limited to feature plugins and Gutenberg, and maybe a handful of other plugins that address things in a specific WordPress release. And all those plugins can just as well include some manual WordPress version checks.

[azaozz]

Replying to swissspidy:

the cases this is useful for is limited to feature plugins and Gutenberg, and maybe a handful of other plugins...

True. But still thinking Compatible up to should be handled by core even if it is only for feature plugins. Would make it easier for them and the plugins will not have to be activated in order to explain why they do not work and cannot be used.

[dd32]

I personally think this is something that plugins should handle themselves, gracefully disabling themselves when they detect that the environment says they're no longer needed.