If you " keep someone posted" , you keep them informed of what's going on.

如果您“让某人保持最新状态”，您就可以让他们了解正在发生的事情。

So if you " keep someone posted" about something, it means you keep them informed -- give them regular updates.

因此，如果您“让某人了解”某事，这意味着您让他们了解情况——定期更新。