keep posted

To continue to inform someone about something so that they have current information. Congratulations on getting that interview! Keep me posted on how it goes! Right now, her condition is stable. We promise to keep you posted as she improves.

Fig. to keep someone informed (of what is happening); to keep someone up to date. If the price of corn goes up, I need to know. Please keep me posted. Keep her posted about the patient's status.

Supply with up-to-date information, as in Keep me posted about your new job. This usage alludes to the accounting practice of posting the latest figures in a ledger. [Early 1800s]

To supply someone with up-to-date information. This term originated in the United States in the early nineteenth century and comes from accounting, where the latest figures entered into a system are said to be “posted.” It originally was put as being posted up, as in “Mr. M. is not well posted up, or he would have said less on this subject” (The Weekly Oregonian, 1854).