diff --git a/build.gradle b/build.gradle
index 6576990..f73e5dc 100644
--- a/build.gradle
+++ b/build.gradle
@@ -20,7 +20,7 @@ subprojects {
 
     group = 'org.cadixdev'
     archivesBaseName = project.name.toLowerCase()
-    version = '0.5.1'
+    version = '0.5.2'
 
     repositories {
         mavenCentral()
diff --git a/changelogs/0.5.2.md b/changelogs/0.5.2.md
new file mode 100644
index 0000000..c3faac7
--- /dev/null
+++ b/changelogs/0.5.2.md
@@ -0,0 +1,5 @@
+Lorenz 0.5.2
+============
+
+Lorenz 0.5.2 addresses issues with using Lorenz's ASM Remapper on Atlas >= 0.2.0.
+Specifically, it should now be possibly to concurrently access mappings.
diff --git a/lorenz/src/main/java/org/cadixdev/lorenz/MappingSet.java b/lorenz/src/main/java/org/cadixdev/lorenz/MappingSet.java
index 947d8f8..6f1bd81 100644
--- a/lorenz/src/main/java/org/cadixdev/lorenz/MappingSet.java
+++ b/lorenz/src/main/java/org/cadixdev/lorenz/MappingSet.java
@@ -25,16 +25,16 @@
 
 package org.cadixdev.lorenz;
 
-import org.cadixdev.lorenz.impl.MappingSetImpl;
-import org.cadixdev.lorenz.model.ClassMapping;
-import org.cadixdev.lorenz.model.TopLevelClassMapping;
-import org.cadixdev.lorenz.model.jar.CascadingFieldTypeProvider;
-import org.cadixdev.lorenz.model.jar.FieldTypeProvider;
 import org.cadixdev.bombe.type.ArrayType;
 import org.cadixdev.bombe.type.FieldType;
 import org.cadixdev.bombe.type.MethodDescriptor;
 import org.cadixdev.bombe.type.ObjectType;
 import org.cadixdev.bombe.type.Type;
+import org.cadixdev.lorenz.impl.MappingSetImpl;
+import org.cadixdev.lorenz.model.ClassMapping;
+import org.cadixdev.lorenz.model.TopLevelClassMapping;
+import org.cadixdev.lorenz.model.jar.CascadingFieldTypeProvider;
+import org.cadixdev.lorenz.model.jar.FieldTypeProvider;
 import org.cadixdev.lorenz.util.Reversible;
 
 import java.util.Collection;
diff --git a/lorenz/src/main/java/org/cadixdev/lorenz/impl/MappingSetImpl.java b/lorenz/src/main/java/org/cadixdev/lorenz/impl/MappingSetImpl.java
index a054539..8004be0 100644
--- a/lorenz/src/main/java/org/cadixdev/lorenz/impl/MappingSetImpl.java
+++ b/lorenz/src/main/java/org/cadixdev/lorenz/impl/MappingSetImpl.java
@@ -32,9 +32,9 @@
 
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * A basic implementation of {@link MappingSet}.
@@ -44,7 +44,7 @@
  */
 public class MappingSetImpl implements MappingSet {
 
-    private final Map<String, TopLevelClassMapping> topLevelClasses = new HashMap<>();
+    private final Map<String, TopLevelClassMapping> topLevelClasses = new ConcurrentHashMap<>();
     private final MappingSetModelFactory modelFactory;
     private CascadingFieldTypeProvider fieldTypeProvider = new CascadingFieldTypeProvider();
 
diff --git a/lorenz/src/main/java/org/cadixdev/lorenz/impl/model/AbstractClassMappingImpl.java b/lorenz/src/main/java/org/cadixdev/lorenz/impl/model/AbstractClassMappingImpl.java
index 81906ef..4c4c13f 100644
--- a/lorenz/src/main/java/org/cadixdev/lorenz/impl/model/AbstractClassMappingImpl.java
+++ b/lorenz/src/main/java/org/cadixdev/lorenz/impl/model/AbstractClassMappingImpl.java
@@ -25,22 +25,22 @@
 
 package org.cadixdev.lorenz.impl.model;
 
+import org.cadixdev.bombe.analysis.InheritanceProvider;
+import org.cadixdev.bombe.type.signature.FieldSignature;
+import org.cadixdev.bombe.type.signature.MethodSignature;
 import org.cadixdev.lorenz.MappingSet;
 import org.cadixdev.lorenz.model.ClassMapping;
 import org.cadixdev.lorenz.model.FieldMapping;
 import org.cadixdev.lorenz.model.InnerClassMapping;
 import org.cadixdev.lorenz.model.MethodMapping;
-import org.cadixdev.bombe.analysis.InheritanceProvider;
-import org.cadixdev.bombe.type.signature.FieldSignature;
-import org.cadixdev.bombe.type.signature.MethodSignature;
 
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.StringJoiner;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * A basic implementation of {@link ClassMapping}.
@@ -55,10 +55,10 @@ public abstract class AbstractClassMappingImpl<M extends ClassMapping, P>
         extends AbstractMappingImpl<M, P>
         implements ClassMapping<M, P> {
 
-    private final Map<FieldSignature, FieldMapping> fields = new HashMap<>();
-    private final Map<String, FieldMapping> fieldsByName = new HashMap<>();
-    private final Map<MethodSignature, MethodMapping> methods = new HashMap<>();
-    private final Map<String, InnerClassMapping> innerClasses = new HashMap<>();
+    private final Map<FieldSignature, FieldMapping> fields = new ConcurrentHashMap<>();
+    private final Map<String, FieldMapping> fieldsByName = new ConcurrentHashMap<>();
+    private final Map<MethodSignature, MethodMapping> methods = new ConcurrentHashMap<>();
+    private final Map<String, InnerClassMapping> innerClasses = new ConcurrentHashMap<>();
     private boolean complete;
 
     /**