diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 86a4d9e..0a088e8 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -11,7 +11,7 @@ mappingsTestDevBundle = "1.20.2-R0.1-SNAPSHOT"
 indra-common = { group = "net.kyori", name = "indra-common", version.ref = "indra" }
 indra-licenser-spotless = { group = "net.kyori", name = "indra-licenser-spotless", version.ref = "indra" }
 indra-publishing-sonatype = { group = "net.kyori", name = "indra-publishing-sonatype", version.ref = "indra" }
-paperweight-userdev = { group = "io.papermc.paperweight.userdev", name = "io.papermc.paperweight.userdev.gradle.plugin", version = "1.5.9" }
+paperweight-userdev = { group = "io.papermc.paperweight.userdev", name = "io.papermc.paperweight.userdev.gradle.plugin", version = "1.5.10" }
 
 mappingsTestDevBundle = { module = "io.papermc.paper:dev-bundle", version.ref = "mappingsTestDevBundle" }
 memoryMeasurer = "com.volkhart.memory:measurer:0.2-SNAPSHOT"
@@ -19,7 +19,7 @@ junit-jupiter-api = "org.junit.jupiter:junit-jupiter-api:5.10.1"
 junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine" }
 
 checker-qual = "org.checkerframework:checker-qual:3.40.0"
-mapping-io = { group = "net.fabricmc", name = "mapping-io", version = "0.4.2" }
+mapping-io = { group = "net.fabricmc", name = "mapping-io", version = "0.5.0" }
 
 cloud-bom = { group = "cloud.commandframework", name = "cloud-bom", version = "1.8.4" }
 cloud-paper = { module = "cloud.commandframework:cloud-paper" }
diff --git a/src/main/java/xyz/jpenilla/reflectionremapper/ReflectionRemapperImpl.java b/src/main/java/xyz/jpenilla/reflectionremapper/ReflectionRemapperImpl.java
index 41e5bc5..4a1f4d5 100644
--- a/src/main/java/xyz/jpenilla/reflectionremapper/ReflectionRemapperImpl.java
+++ b/src/main/java/xyz/jpenilla/reflectionremapper/ReflectionRemapperImpl.java
@@ -109,22 +109,22 @@ static ReflectionRemapperImpl fromMappingTree(
       final Map<String, String> fields = new HashMap<>();
       for (final MappingTree.FieldMapping field : cls.getFields()) {
         fields.put(
-          pool.string(field.getName(fromNamespace)),
-          pool.string(field.getName(toNamespace))
+          pool.string(Objects.requireNonNull(field.getName(fromNamespace))),
+          pool.string(Objects.requireNonNull(field.getName(toNamespace)))
         );
       }
 
       final Map<String, String> methods = new HashMap<>();
       for (final MappingTree.MethodMapping method : cls.getMethods()) {
         methods.put(
-          pool.string(methodKey(method.getName(fromNamespace), method.getDesc(toNamespace))),
-          pool.string(method.getName(toNamespace))
+          pool.string(methodKey(Objects.requireNonNull(method.getName(fromNamespace)), Objects.requireNonNull(method.getDesc(toNamespace)))),
+          pool.string(Objects.requireNonNull(method.getName(toNamespace)))
         );
       }
 
       final ClassMapping map = new ClassMapping(
-        cls.getName(toNamespace).replace('/', '.'),
-        cls.getName(fromNamespace).replace('/', '.'),
+        Objects.requireNonNull(cls.getName(toNamespace)).replace('/', '.'),
+        Objects.requireNonNull(cls.getName(fromNamespace)).replace('/', '.'),
         Collections.unmodifiableMap(fields),
         Collections.unmodifiableMap(methods)
       );