I'm currently running OpenIB and PHP 7.1 (9san.ch)
All the new software (lynx) is horrible to look at and not at all better than our age old rusty, but working and easily modifiable software.
OpenIB is beyond broken though. vichan is a lot easier to get running properly than OpenIB and it's basically the same thing anyways minus a few features (like board creation). And as you can see on 8kun, OpenIB looks disgusting by default lol.. I'm new to OpenIB, but I've worked with vichan for many years.
Also you gotta change the youtube embed to https now, cause mixed content (http+https) is bad and my browser blocks the embed iframe from loading.
If you're not using anything important in Apache I would also recommend nginx because it doesn't look like HTTP/3 is coming to Apache any time soon(?), whereas nginx already has it. Most browsers have http3 disabled by default though so it doesn't matter yet nor does it really make a huge difference for smaller sites, but it is a speed increase available soon.
Honestly besides setting up some JS like quick-reply, ajax(based) and stuff like that, there's not that much you need to do. A community is much more important than anything else.