diff --git a/moa/pom.xml b/moa/pom.xml
index c8387b9fa..a17fab398 100755
--- a/moa/pom.xml
+++ b/moa/pom.xml
@@ -4,7 +4,7 @@
   <parent>
     <groupId>nz.ac.waikato.cms.moa</groupId>
     <artifactId>moa-pom</artifactId>
-    <version>2020.05.0-HOTFIX</version>
+    <version>2020.05.1</version>
   </parent>
 
   <artifactId>moa</artifactId>
diff --git a/moa/src/main/java/moa/core/AutoClassDiscovery.java b/moa/src/main/java/moa/core/AutoClassDiscovery.java
index bbb98a1d1..b33ab37f4 100644
--- a/moa/src/main/java/moa/core/AutoClassDiscovery.java
+++ b/moa/src/main/java/moa/core/AutoClassDiscovery.java
@@ -62,7 +62,7 @@ protected static synchronized void initCache() {
             if (m_Cache.getClassnames("moa.classifiers.trees").isEmpty()) {
                 InputStream inputStream = null;
                 try {
-                    inputStream = m_Cache.getClass().getResourceAsStream(CLASS_LIST);
+                    inputStream = m_Cache.getClass().getClassLoader().getResourceAsStream(CLASS_LIST);
                     m_Cache = new ClassCache(new FixedClassListTraversal(inputStream));
                 }
                 catch (Exception e) {
diff --git a/pom.xml b/pom.xml
index 7957711ca..fc8c37e3d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
   <groupId>nz.ac.waikato.cms.moa</groupId>
   <artifactId>moa-pom</artifactId>
   <packaging>pom</packaging>
-  <version>2020.05.0-HOTFIX</version>
+  <version>2020.05.1</version>
 
   <name>MOA: meta-package</name>
   <description>
diff --git a/release.xml b/release.xml
index baaef936c..57b79177a 100644
--- a/release.xml
+++ b/release.xml
@@ -4,7 +4,7 @@
   <parent>
     <groupId>nz.ac.waikato.cms.moa</groupId>
     <artifactId>moa-pom</artifactId>
-    <version>2020.05.0-HOTFIX</version>  <!-- adjust -->
+    <version>2020.05.1</version>  <!-- adjust -->
   </parent>
 
   <artifactId>moa-release</artifactId>
diff --git a/weka-package/Description.props b/weka-package/Description.props
index 39fa3ea23..15a6bca94 100644
--- a/weka-package/Description.props
+++ b/weka-package/Description.props
@@ -2,10 +2,10 @@
 PackageName=massiveOnlineAnalysis
 
 # Version (required)
-Version=2020.05.0-HOTFIX
+Version=2020.05.1
 
 #Date
-Date=2020-05-13
+Date=2020-05-19
 
 # Title (required)
 Title=MOA (Massive On-line Analysis).
@@ -27,7 +27,7 @@ Description=Massive On-line Analysis is an environment for massive data mining.
 Changes=
 
 # Package URL for obtaining the package archive (required)
-PackageURL=https://github.com/Waikato/moa/releases/download/2020.05.0-HOTFIX/massiveOnlineAnalysis-2020.05.0-HOTFIX.zip
+PackageURL=https://github.com/Waikato/moa/releases/download/2020.05.1/massiveOnlineAnalysis-2020.05.1.zip
 
 # URL for further information
 URL=http://moa.cs.waikato.ac.nz/
diff --git a/weka-package/pom.xml b/weka-package/pom.xml
index 5cbe0796e..3cece6c7c 100644
--- a/weka-package/pom.xml
+++ b/weka-package/pom.xml
@@ -6,7 +6,7 @@
   <parent>
     <groupId>nz.ac.waikato.cms.moa</groupId>
     <artifactId>moa-pom</artifactId>
-    <version>2020.05.0-HOTFIX</version>
+    <version>2020.05.1</version>
   </parent>
 
   <artifactId>weka-package</artifactId>
diff --git a/weka-package/update_libs.xml b/weka-package/update_libs.xml
index f4c00e055..d7f623874 100644
--- a/weka-package/update_libs.xml
+++ b/weka-package/update_libs.xml
@@ -6,7 +6,7 @@
   <parent>
     <groupId>nz.ac.waikato.cms.moa</groupId>
     <artifactId>moa-pom</artifactId>
-    <version>2020.05.0-HOTFIX</version>
+    <version>2020.05.1</version>
   </parent>
 
   <artifactId>weka-package</artifactId>