How is it usually determined whether the database in the application is up to date?

Question

PostgreSQL

Kind
Let's say there is an application, at the first start it downloads data from the server and writes it to sqlite. After some time, the data on the server was updated. As usual, let the application know that the table needs to be updated. After all, applications have different data (they are updated only if possible, i.e. several updates could have already been released), while not demolishing the entire database, but only making up for the difference in data with the server, i.e. add new data, leaving the existing ones unchanged