A Delphi Android project consists not only the Delphi code files but Java Classes and Android Manifest files which change with each release of Delphi as it "Targets" later versions of Android. The SDK is also likely to change.
The project files contain information about the Android SDK and Template files are copied to the project directory. If you open a project which compiled in an earlier version of Delphi it will likely have troubles as remnants of old configurations remain.
For "service" projects the service link is also embedded in the project files so changing the name of the service causes more remnant misinformation.
The software to interact with the hardware (??PAServer??) may change also.
The help files suggest the following
"Under the Android target in Project Manager, right-click the Libraries node and click “Revert System Files To Default”, then rebuild."
Revert to the Default SDK >> Right Click the Android Target Platform
