# Surrogate-Control controls our CDN, Cache-Control downstream caches
if ( $this->mConfig->get( 'UseESI' ) ) {
+ wfDeprecated( '$wgUseESI = true', '1.33' );
header( 'Surrogate-Control: max-age=' . $this->mCacheDuration . ', content="ESI/1.0"' );
header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
} else {