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Secondly you don't need to use component specific version for every project but you don't need to do anything special to enable or disable plugin project by project. If you don't define any component specific version for within versio within a project's administrative section this project continues to work as if plugin is not installed. Even if you define one component specific version, the plugin is enabled for that project. For other areas there are similar opt-out mechanisms exist in the add-on settings.
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