Manually creating a copy of your theme | HCL Digital Experience
You need to create your own custom theme by copying the Portal Version 8.5 theme before you start customization. You should create a copy of both the static and dynamic content even if you plan to modify files from only one. When you create copies of both your static and dynamic theme content, you ensure that your theme has all of the required elements that it needs to function. You also ensure that changes to any of the theme files in future Combined Cumulative Fixes do not affect your theme.
To create a copy of your theme by using the Theme Manager, see Copy Theme.
Note: Do not modify the Portal Version 8.5 theme directly, because
this theme can be updated by service fix packs and override your changes.