In Eclipse are different places where you can change the version of your web application.

1. Your pom.xml
Change the version of your artifact like:

<groupId>de.uni_leipzig.smo</groupId>
<artifactId>trialregistry-gui</artifactId>
<version>0.3-SNAPSHOT</version>
<packaging>war</packaging>

2. Your build path
Set the default output folder to something similar to your pom.xml:

3. Your Run configuration
To run GWT applications you define a Run configration within Eclipse. The tab “Arguments” contains also a path to the war-directory, which could contain the version number: