In eXo Platform 4, upgrading is guaranteed and tested as follows:
This means you should upgrade to a version from its nearest one. For example, if you want to upgrade from 4.0.1 to 4.0.3, you should upgrade from 4.0.1 to 4.0.2, then from 4.0.2 to 4.0.3. However, if you still insist on skipping versions, it is strongly advised you read all release notes of versions you are skipping to see which of any previous upgrade procedure impacts your project.
Upgrading to a newer version
Stop the old version of eXo Platform.
Apply your customizations into the new version. If you use a populated organizational data source (such as LDAP), activate the Organization Integration Service so that the data is synchronized. See Synchronization for more details.
Configure the JCR and IDM databases. Refer to Database for more details.
Configure the EXO_DATA_DIR variable. Refer to Data directory configuration for more details.
Activate the necessary plugin(s), as described in Release Notes, in the
$PLATFORM_TOMCAT_HOME/gatein/conf/configuration.properties (in Tomcat) or
$PLATFORM_JBOSS_HOME/standalone/configuration/gatein/configuration.properties (in JBoss) file.
For example, from 4.0.0 to 4.0.1:
Start the server. The startup is successful when you see a message like INFO | Server startup in XXXX ms.
Stop the server.
Disable the upgrade plugin(s) in Step 5 by changing "true" into "false". This is to avoid running the upgrade again for next time.
Restart the server, then do some tests on the upgraded version. See Best practices for more details.