Disclaimer:

To get old terrain to generate, you'll need to enter moderner_beta\:moderner_beta in level-type from server.properties.

• added Better End mod.
• added The Aether mod.
• added Revamped Phantoms mod.
• improved Legacy 4J crafting recipes.
• improved Overworld, Nether and End world borders.
• improved skyboxes for all resource assorts.
• updated limited worlds version from 0.0.5 to 0.0.53-endislands.18.
• removed Illager invasion mod.
• removed Twilight Forest mod. (copyright)

• Endermen now emulate their old behaviour. video.

If an enderman is damaged by a player it will immediately teleport (this contrasts their modern behaviour where they only have a slight chance to teleport away upon player-sourced damage)

• Ported the 'no trims' module from Classic Mechanics v1.13.0
• Removes trims from equipped armor pieces (if there are any)

Done by @Wilozyx