renovate/lib/modules/manager/travis/readme.md

This manager is intended to keep Travis config files (.travis.yml) up-to-date, this file controls the CI build environment. Currently Renovate can only update the node_js section of this file.

Renovate "understands" Travis's Build Matrix concept as well, so it will try to update all found Node.js versions to the latest LTS, e.g.

node_js:
-  - 8.10.0
-  - 10.10.0
+  - 16.13.0
+  - 16.13.0

Due to this, major updates for Travis are disabled by default. If you enable major updates and use a version matrix, then you will likely need to manually fix any major update PRs raised by Renovate. Here's how to enable major updates in your Renovate config:

{
  "travis": {
    "major": {
      "enabled": true
    }
  }
}