Bringing something up to date means to update, MODERNIZE, REVISE, and rear it. This could refer to a variety of things, such as technology, a document, or even a person's skillset. Updating something would involve making changes to keep it current and relevant. Modernizing something would involve making changes to make it more modern and up-to-date. Revising something would involve making changes to improve it. Rearring something would involve making changes to bring it back to its original state.