Upstream has released updates that appears to apply and compile correctly.
This update has been tested to ensure that World Conversion still occurs correctly.
Bukkit Changes:
0812ce2c SPIGOT-4397: isChunkGenerated API
CraftBukkit Changes:
4824655c SPIGOT-4398: Upgrade to ASM 6.2.1 for better Java 11 support
eea43870 MC-134115: Fix issues converting tile entities
1a7f2d10 SPIGOT-4397: isChunkGenerated API
40aed54d SPIGOT-4396: Improve vehicle movement
Spigot Changes:
f6a273b1 Rebuild patches
Updated Upstream (Bukkit/CraftBukkit/Spigot)
Bukkit Changes:
2dcc44dc SPIGOT-4307: Fix hacky API for banners on shields
e0fc6572 SPIGOT-4309: Add "forced" display of particles
efeeab2f Add index to README.md for easier navigation
f502bc6f Update to Minecraft 1.13.1
CraftBukkit Changes:
d0bb0a1d Fix some tests randomly failing
997d378d Fix client stall in specific teleportation scenarios
b3dc2366 SPIGOT-4307: Fix hacky API for banners on shields
2a271162 SPIGOT-4301: Fix more invalid enchants
5d0d83bb SPIGOT-4309: Add "forced" display of particles
a6772578 Add additional tests for CraftBlockData
ce1af0c3 Update to Minecraft 1.13.1
Spigot Changes:
2440e189 Rebuild patches
4ecffced Update to Minecraft 1.13.1