The app "cannot be opened because the developer cannot be verified." Is there a workaround or a verified version of the app?

For various reasons, I need to have my computer's IP address be static. Unfortunately, despite putting it into the DHCP/Address Reservation table, it winds up being non-static. Why is that and how do

Note: I am not using the standard released firmware (Build 150xxxx) because address reservations do not work at all. Tp-link support has an internal release that does the job (this one). However, if S