Unable to customise admin panel or change its language options

System Information
  • Strapi Version: 4.2.0
  • Operating System: Linux Alpine (running on a Node 16 Docker container)
  • Database: Postgres
  • Node Version: 16
  • NPM Version: 8.11

Hi, I am unable to change the admin panel UI language or customise the titles. I’ve followed the docs and changed the file ./src/admin/app.js to something like the following:

export default {
  config: {
    locales: ['de'],
    translations: {
      de: {
        'app.components.LeftMenu.navbrand.title': 'Titel',
        'app.components.LeftMenu.navbrand.workplace': 'Untertitel',
      en: {
        'app.components.LeftMenu.navbrand.title': 'Title',
        'app.components.LeftMenu.navbrand.workplace': 'Subtitle',
    // Disable video tutorials
    tutorials: false,
    // Disable notifications about new Strapi releases
    notifications: { releases: false },
  bootstrap(app) {},

But none of these changes are applied. I am not sure if it is something related to the fact that I am running Strapi inside a Docker container. I have deleted the container and the image, rebuild, and still I don’t see the custom titles or the German language option for the admin UI.

Any recommendations are much appreciated. Thanks!