Two OpenHabs?

I’ve been running OpenHab v1.6 on an Rpi2 for some time under the hostname openhab. I’ve recently started testing OpenHab on a Pine64 with the hostname openhab2. For some reason my android app is “randomly” switching between the two instances of OpenHab. I only want to use them simultaneously while I get the new system up and running. What am I missing to always have my Android apps point to my original OpenHab install?

Also, is there any reason why I should or should not change my new install to hostname openhab from openhab2 after I get everything moved over?