You’ll need phonegap/cordova and build the app locally as adobe discontinued the phonegap build service and more.
See here for more information: https://blog.phonegap.com/update-for-customers-using-phonegap-and-phonegap-build-cc701c77502c
On a previous Mx7 project we also used phonegap for building the apk. Now in a Mx8 project, we use a beta-version of the NBUI, the Native Builder UserInterface. This will be released with Mx 8.15 and make that building easier, but it is only for native apps. It is probably not an option to switch, just for this.