For more information, see Sonatype's documentation: Upgrading Nexus Repository Manager 3.1.0 and Newer.
The following section describes how to migrate from an existing 3.x Talend Artifact Repository instance to a 3.15.2 Talend Artifact Repository instance while keeping your configuration settings and the artifacts you have previously published to the repository. The new Talend Artifact Repository configuration will be merged with your existing data at the next start-up.
In the Talend Artifact Repository installation directory, the sonatype-work folder is the Talend Artifact Repository data directory that contains the Talend Artifact Repository configuration and data storage (repositories, settings, logs, published artifacts, and so on).
For more information on the different Nexus directories, read the Sonatype Nexus documentation.
To back up the existing Talend Artifact Repository data:
Log a Support case to have the following patch assigned to you: Patch_20190326_TPS-2996_v3-7.0.1.zip.
Log a Support case to have the following patch assigned to you: Patch_20190326_TPS-2995_v2-7.1.1.zip.
Talend patch TPS-XXXX must be installed before upgrading to Nexus 3.15.2.
Contact the Support team if you require additional clarification.