Get an error on activation that persists throughout

Strict standards: Declaration of WPUF_Walker_Category_Checklist::start_lvl() should be compatible with Walker::start_lvl(&$output, $depth = 0, $args = Array) in \wp-content\plugins\wp-user-frontend\wpuf.php on line 15

Strict standards: Declaration of WPUF_Walker_Category_Checklist::end_lvl() should be compatible with Walker::end_lvl(&$output, $depth = 0, $args = Array)

Strict standards: Declaration of WPUF_Walker_Category_Checklist::start_el() should be compatible with Walker::start_el(&$output, $object, $depth = 0, $args = Array, $current_object_id = 0)

Strict standards: Declaration of WPUF_Walker_Category_Checklist::end_el() should be compatible with Walker::end_el(&$output, $object, $depth = 0, $args = Array)

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