Now the time has come. 1.16.1 has been released and gives all server owners happy sleepless nights. I hereby submit my modest contribution to it :)

Spigot-Version: CraftBukkit version git-Spigot-758abbe-38de0b8 (MC: 1.16.1) (Implementing API version 1.16.1-R0.1-SNAPSHOT)

[05:44:29] [Server thread/ERROR]: Could not load 'plugins\Shopkeepers-2.9.3.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException:
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:139) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:394) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:301) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
at org.bukkit.craftbukkit.v1_16_R1.CraftServer.loadPlugins(CraftServer.java:377) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
at net.minecraft.server.v1_16_R1.DedicatedServer.init(DedicatedServer.java:186) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
at net.minecraft.server.v1_16_R1.MinecraftServer.v(MinecraftServer.java:808) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
at net.minecraft.server.v1_16_R1.MinecraftServer.lambda$0(MinecraftServer.java:164) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_231]
Caused by: java.lang.NoSuchFieldError: PIG_ZOMBIE
at com.nisovin.shopkeepers.Settings.(Settings.java:166) ~[?:?]
at com.nisovin.shopkeepers.shopobjects.living.SKLivingShopObjectTypes.(SKLivingShopObjectTypes.java:145) ~[?:?]
at com.nisovin.shopkeepers.shopobjects.living.LivingShops.(LivingShops.java:14) ~[?:?]
at com.nisovin.shopkeepers.SKShopkeepersPlugin.(SKShopkeepersPlugin.java:118) ~[?:?]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_231]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_231]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_231]
at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_231]
at java.lang.Class.newInstance(Unknown Source) ~[?:1.8.0_231]
at org.bukkit.plugin.java.PluginClassLoader.(PluginClassLoader.java:76) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[minecraft_server.jar:git-Spigot-758abbe-38de0b8]
... 7 more

i can agree this

[07:55:22] [Server thread/ERROR]: Could not load 'plugins\Shopkeepers-2.9.3.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoSuchFieldError: PIG_ZOMBIE
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:139) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:394) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:301) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	at org.bukkit.craftbukkit.v1_16_R1.CraftServer.loadPlugins(CraftServer.java:377) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	at net.minecraft.server.v1_16_R1.DedicatedServer.init(DedicatedServer.java:186) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	at net.minecraft.server.v1_16_R1.MinecraftServer.v(MinecraftServer.java:808) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	at net.minecraft.server.v1_16_R1.MinecraftServer.lambda$0(MinecraftServer.java:164) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	at java.lang.Thread.run(Thread.java:832) [?:?]
Caused by: java.lang.NoSuchFieldError: PIG_ZOMBIE
	at com.nisovin.shopkeepers.Settings.<clinit>(Settings.java:166) ~[?:?]
	at com.nisovin.shopkeepers.shopobjects.living.SKLivingShopObjectTypes.<init>(SKLivingShopObjectTypes.java:145) ~[?:?]
	at com.nisovin.shopkeepers.shopobjects.living.LivingShops.<init>(LivingShops.java:14) ~[?:?]
	at com.nisovin.shopkeepers.SKShopkeepersPlugin.<init>(SKShopkeepersPlugin.java:118) ~[?:?]
	at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?]
	at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:?]
	at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?]
	at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) ~[?:?]
	at java.lang.reflect.ReflectAccess.newInstance(ReflectAccess.java:124) ~[?:?]
	at jdk.internal.reflect.ReflectionFactory.newInstance(ReflectionFactory.java:346) ~[?:?]
	at java.lang.Class.newInstance(Class.java:604) ~[?:?]
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:76) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[spigot-1.16.1.jar:git-Spigot-758abbe-38de0b8]
	... 7 more

Same here, I got the exact same error. Seems that other plugins and datapacks are now messed up because of the removal of the Zombie Pigman in 1.16.1.

The problem can be solved by replacing the following list in the config:

https://pastebin.com/5v52va6N

Then Shopkeeper goes again perfectly in 1.16.1

Nope, changing that in the config still doesnt work.

This error is resolved by using the latest version of Spigot 1.16.1.

However, this alone doesn't make Shopkeepers safe to be used on MC 1.16.x yet. An update is on the way.

v2.10.0 has been uploaded and includes the update for MC 1.16.1.