I don't want my app in the Play store but my users want an auto-update

I have designed and deployed an app that my company uses and the fleet wants updates to automatically happen. Does anyone know how to accomplish this without having to post the app in the Play Store?

Facebook actually does this, able to update apps directly without going through the Play Store. I'd guess you'd need your own servers and the app has to be programmed to query for updates to trigger a download and install. Too much of a hassle and cost IMO to just not use the Play Store. Any reason why you don't want to use the store? I mean you could publish apps privately to be accessible only by members of your company: https://support.google.com/googlepla.../6145139?hl=en