The Brexit How to guide has just been published in the Online help center.
This document details how to adapt the VAT set-up due to the end of the transition period for Brexit, December 31, 2020, from a UK perspective. It focuses on VAT management impacts.
The information here is specific to Sage X3 versions 11 or 12. If you run another version, significant differences could occur in functionalities and you could have serious difficulties to submit your VAT returns in the Making Tax Digital (MTD) context.
Useful information for all products is also available at Sage Brexit Hub.