Yes, I know that, but Nik 6.3 does not remove an older Nik and therefore, DxO has started to make parallel installations possible, which implies, imo, that DxO will have to provide support for such installations.
On my iMac, Nik versions 5 and 6.3 work side by side standalone and as Lightroom plugins (have not tested other configs) without apparent issues. Read more about it here: