End of light mob farm

The general mob farm from the HammerSMP End of Light video, which shows several light suppressed farms. Light suppression keeps nether portals, cut to one block tall, at light level 0, so mobs spawn inside the portal blocks and go through to the nether side, where killing chambers wait.

It runs on one player's mob cap and needs a bat switch, or bats flood the portals and crash the game. Building it takes light suppression, update suppression and crashing the server on purpose, and the finished farm breaks chunk loading. It suits technical players with a strong server. The team designed it in creative with /fill, and the creator says he would never build it in survival.

• Lay a lightning proof floor of bottom slabs around the farm. Fire from a strike causes light updates. The creator and team member SRAZKVT (139 likes) both warn about it.
• Keep every chunk the farm needs loaded with real players or bots. The farm breaks chunk loading, and loading those chunks again crashes the game fast. Creator's comment.
• Build the bat switch the video marks as required. Without it bats spawn in the portals, pile up in the nether and crash the game. Comment with 943 likes and a team member.
• Check that update suppression works in your version before you start. The team removes the portal obsidian with it, and four commenters say it is patched, one naming 1.19.
• Open the world download in 1.15. A team member says it relies on portal POIs, and builders on 1.16.2 and 1.18.1 say nothing works in it.
• Expect heavy lag. The creator's own run sat at 48 mspt on a strong server, and he says Lithium saves about 15 to 20 mspt.