Error

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Standards: call_user_func_array() expects parameter 1 to be a valid callback, non-static method warm_cache::addPluginSubMenu() should not be called statically in /home2/freefiles/public_html/……/wp-includes/class-wp-hook.php on line 298

Strict Standards: Non-static method mijnpress_plugin_framework::addPluginSubMenu() should not be called statically in /home2/freefiles/public_html/—–/wp-content/plugins/warm-cache/warm-cache.php on line 148