diff --git a/Mustang-CLI/pom.xml b/Mustang-CLI/pom.xml
index 58eb2d15..03865762 100644
--- a/Mustang-CLI/pom.xml
+++ b/Mustang-CLI/pom.xml
@@ -3,14 +3,14 @@
 <parent>
     <groupId>org.mustangproject</groupId>
     <artifactId>core</artifactId>
-    <version>2.9.1-SNAPSHOT</version>
+    <version>2.7.4-SNAPSHOT</version>
 </parent>
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.mustangproject</groupId>
    <artifactId>Mustang-CLI</artifactId>
    <name>e-invoices commandline tool, allowing to create(embed), split and validate Factur-X/ZUGFeRD files. Validation should also work for XRechnung/CII. </name>
    <packaging>jar</packaging>
-   <version>2.9.1-SNAPSHOT</version>
+   <version>2.7.4-SNAPSHOT</version>
    <properties>
       <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
       <maven.compiler.compilerVersion>8</maven.compiler.compilerVersion>
@@ -21,7 +21,7 @@
       <dependency>
          <groupId>org.mustangproject</groupId>
          <artifactId>validator</artifactId>
-         <version>2.9.1-SNAPSHOT</version>
+         <version>2.7.4-SNAPSHOT</version>
          <!-- prototypes of new mustangproject versions can be installed by referring to them and installed to the local repo from a jar file with
         mvn install:install-file -Dfile=mustang-1.5.4-SNAPSHOT.jar -DgroupId=org.mustangproject.ZUGFeRD -DartifactId=mustang -Dversion=1.5.4 -Dpackaging=jar -DgeneratePom=true
         -->
diff --git a/library/pom.xml b/library/pom.xml
index e2d19282..960e678c 100644
--- a/library/pom.xml
+++ b/library/pom.xml
@@ -3,13 +3,13 @@
 <parent>
     <groupId>org.mustangproject</groupId>
     <artifactId>core</artifactId>
-    <version>2.9.1-SNAPSHOT</version>
+    <version>2.7.4-SNAPSHOT</version>
 </parent>
 
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.mustangproject</groupId>
 	<artifactId>library</artifactId>
-	<version>2.9.1-SNAPSHOT</version>
+	<version>2.7.4-SNAPSHOT</version>
 	<packaging>jar</packaging>
 	<name>Library to write, read and validate e-invoices (Factur-X, ZUGFeRD, Order-X, XRechnung/CII)</name>
 	<description>FOSS Java library to read, write and validate european electronic invoices and orders in the UN/CEFACT Cross Industry Invoice based formats Factur-X/ZUGFeRD, XRechnung and Order-X in your invoice PDFs.
diff --git a/pom.xml b/pom.xml
index 6fc651fd..0690658d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -3,7 +3,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>org.mustangproject</groupId>
     <artifactId>core</artifactId>
-    <version>2.9.1-SNAPSHOT</version>
+    <version>2.7.4-SNAPSHOT</version>
     <packaging>pom</packaging>
     <name>Mustang</name>
 
diff --git a/validator/pom.xml b/validator/pom.xml
index 9921d9d5..71824a56 100644
--- a/validator/pom.xml
+++ b/validator/pom.xml
@@ -3,7 +3,7 @@
     <parent>
         <groupId>org.mustangproject</groupId>
         <artifactId>core</artifactId>
-        <version>2.9.1-SNAPSHOT</version>
+        <version>2.7.4-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
     <groupId>org.mustangproject</groupId>
@@ -11,7 +11,7 @@
     <name>Library to validate e-invoices (ZUGFeRD, Factur-X and Xrechnung)</name>
 
     <packaging>jar</packaging>
-    <version>2.9.1-SNAPSHOT</version>
+    <version>2.7.4-SNAPSHOT</version>
     <repositories>
         <repository>
             <!-- for jargs -->
@@ -38,7 +38,7 @@
         <dependency>
             <groupId>${project.groupId}</groupId>
             <artifactId>library</artifactId>
-            <version>2.9.1-SNAPSHOT</version>
+            <version>2.7.4-SNAPSHOT</version>
         </dependency>
         <!-- for java9 -->
         <dependency>
@@ -98,7 +98,7 @@
         <dependency>
             <groupId>org.mustangproject</groupId>
             <artifactId>library</artifactId>
-            <version>2.9.1-SNAPSHOT</version>
+            <version>2.7.4-SNAPSHOT</version>
         </dependency>
         <dependency>
             <groupId>org.xmlunit</groupId>