Update an existing android's mobile app interface to using new design / UI features

General information for the business: Development Software company
Kind of development: Customization of existing program
Num. of modules: 25 approx.
Description of every module: To update an existing android application (for internal business usage within the care home industry) - and to update every drawable resources screen (18 screens + 4 menus) to a new provided design (in XD format) so it has a consistent look and feel across all screens.
Description of requirements/functionality: To edit every screen resource with its buttons, layouts, fields and dropdowns within the 18 screens to ensure they match the user interface design provided. The screens generally fit on one screen length (so no long screens). The functionality already built is to remain the same - its only the design that needs updating and reflected within the screens. The UI is to ensure the system works easily for the end user - so you will be responsible for ensuring this is delivered within the changes to be made.

Screens need to work for different handset screens (though mobile only - not tablet). The look and feel must be consistent and match the provided within the XD designs. (We can provide these designs once we have received a copy of the signed NDA. The design will be made available online and can be downloaded with all assets, icons and graphics you need to deliver this.
Specific technologies required: Android Studio / Android developer licence maybe required for testing purposes
Extra notes: The project will require the signing of a NDA.

We need to have the software delivered back with all new design change being made applied.