This document discusses a new incremental method for updating approximations in a variable precision rough-set model when objects in an information system are dynamically changing over time. The method utilizes previous data structures to efficiently carry out incremental updates to approximations as objects evolve. It also considers changes to an attribute's domain to update approximations incrementally under a variable precision rough-set model. An experimental evaluation demonstrates the efficiency of the proposed incremental updating method for dynamic maintenance of approximations.