Vibrant Visuals won't work on worlds that were created before 1.26.40

Any worlds with add-ons created before 1.26.40 will straight up not allow me to use Vibrant Visuals on them. New worlds created after this work just fine with VV, but worlds before this just prohibit Vibrant Visuals altogether and force the Fancy or Simple graphics. Even if I remove the add-ons, it will still prohibit Vibrant Visuals. Please help, if you can. Thanks.