diff --git a/build.gradle b/build.gradle
index 750431d047..4adf6ade7f 100644
--- a/build.gradle
+++ b/build.gradle
@@ -28,7 +28,7 @@ def ENV = System.getenv()
 // Fetch build number from Jenkins
 def build_number = ENV.BUILD_NUMBER ?: "local"
 
-def yarnVersion = "${minecraft_version}.$build_number"
+def yarnVersion = "${minecraft_version}+build.$build_number"
 
 
 repositories {
diff --git a/mappings/cpy.mapping b/mappings/cpy.mapping
new file mode 100644
index 0000000000..77816c21d5
--- /dev/null
+++ b/mappings/cpy.mapping
@@ -0,0 +1 @@
+CLASS cpy
diff --git a/mappings/net/minecraft/realms/RealmsObjectSelectionListProxy.mapping b/mappings/net/minecraft/realms/RealmsObjectSelectionListProxy.mapping
new file mode 100644
index 0000000000..ea7e91d56f
--- /dev/null
+++ b/mappings/net/minecraft/realms/RealmsObjectSelectionListProxy.mapping
@@ -0,0 +1 @@
+CLASS net/minecraft/realms/RealmsObjectSelectionListProxy