I wouldn't call it a hard fork, more a downstream derivative. In a similar way, Ubuntu rebases itself on debian unstable every 6 months or so.
That is to say Duval based his product on whichever LineageOS release was 'current' at the time but plans to sync to the next available release when his next development cycle allows (which is Oreo, currently).
That is to say Duval based his product on whichever LineageOS release was 'current' at the time but plans to sync to the next available release when his next development cycle allows (which is Oreo, currently).