Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
Bukkit Changes:
0969eedc Clarify furnace burn time behaviour as per SPIGOT-844
16453bfd SPIGOT-4503: Add API to insert complete ItemStack into Jukebox
CraftBukkit Changes:
dff66dfc Reduce copying of positions from block states
91cae6ef SPIGOT-4387: Durability looping from cancelled BlockPlaceEvent
24c5e68c SPIGOT-4493: Allow burnt out furnaces to remain lit like Vanilla whilst retaining SPIGOT-844 API
bc943daf Fix Jukebox API not synchronizing playing data with state
fe89a8c1 SPIGOT-4503: Add API to insert complete ItemStack into Jukebox
fc102494 Make CraftBlockState use BlockPosition
89ab4887 SPIGOT-4543: Jukebox playing calls should not use legacy data
6ff5a64c SPIGOT-4541: Cancelled bucket events require inventory update
it used public method instead of private, and moved to world config
also improved the implementation to not use obfuscated stuff
Also removed the Fix Double chest conversion patch since its
fixed in other ways in vanilla
It is not immediately clear how these characters ended up on signs in
previous versions. It is clear, however, that they now render as empty
unicode boxes in 1.13, whereas previously they rendered as invisible
characters.
When these signs are loaded in versions after this commit, these
characters from the private use area of the Unicode block will be
stripped. The sign will then be marked to ensure this conversion only
runs once.
There is a flag -DPaper.keepInvalidUnicode=true that can be used if you
do not want us to strip these characters from your signs, though I can
think of no reason to use it.
Fixes GH-1571