SOGo is used for accessing your mails via a webbrowser, adding and sharing your contacts or calendars. For a more in-depth documentation on SOGo please visit its [own documentation](http://wiki.sogo.nu/).
Please check the AngularJS Material [intro](https://material.angularjs.org/latest/Theming/01_introduction) and [documentation](https://material.angularjs.org/latest/Theming/03_configuring_a_theme) as well as the [material style guideline](https://material.io/archive/guidelines/style/color.html#color-color-palette) to learn how this works.
mailcow builds after 30 January 2021 can change SOGo's favicon by replacing `data/conf/sogo/custom-favicon.ico` for SOGo and `data/web/favicon.png` for mailcow UI.
To note: you can use `.png` favicons for SOGo, by renaming them to `custom-favicon.ico`.
For both SOGo and mailcow UI faviconsyou need use one of standard dimensions: 16x16, 32x32, 64x64, 128x128 and 256x256.