diff --git a/CHANGELOG.md b/CHANGELOG.md
index f2315f3..a1ba41c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+## [2.2.2] - 2022-01-23
+- fixed empty cardinals (e.g. "1000" -> "") in FilterKeys result
+
 ## [2.2.1] - 2022-12-21
 - fixed missing scripts in bin distribution
 
diff --git a/pom.xml b/pom.xml
index 6de1181..b720935 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>groupId</groupId>
     <artifactId>totalngrams</artifactId>
-    <version>2.2.1</version>
+    <version>2.2.2</version>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -15,7 +15,8 @@
         <!--  Use the release flag only if you are using Java 9+  -->
         <!--  <maven.compiler.release>8</maven.compiler.release>  -->
         <!-- verbose is useful for debugging purposes -->
-        <maven.compiler.verbose>true</maven.compiler.verbose>     </properties>
+        <maven.compiler.verbose>true</maven.compiler.verbose>
+    </properties>
 
     <build>
         <resources>
diff --git a/src/main/java/org/ids_mannheim/TotalNGrams.java b/src/main/java/org/ids_mannheim/TotalNGrams.java
index be0ffa5..4b481b4 100644
--- a/src/main/java/org/ids_mannheim/TotalNGrams.java
+++ b/src/main/java/org/ids_mannheim/TotalNGrams.java
@@ -17,7 +17,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
-@CommandLine.Command(mixinStandardHelpOptions = true, name = "totalngrams", version = "2.2.1", description = "sum ngram counts from KorAP-XML, CoNLL-U files and frequency lists")
+@CommandLine.Command(mixinStandardHelpOptions = true, name = "totalngrams", version = "2.2.2", description = "sum ngram counts from KorAP-XML, CoNLL-U files and frequency lists")
 
 public class TotalNGrams implements Callable<Integer> {
     static public final Logger logger;