This message appears if an older scene (Corona 5 or older) is opened in Corona 6 or newer.
To keep the new rendering consistent with the old one, Corona will by default enable the old Bloom and Glare effect. If you wish to enable the new, improved, Bloom and Glare effect with additional aperture controls, you can do it by either clicking on the "here" link in the error message itself, or you can enable it manually in the VFB > Post > Bloom and Glare section.