I found when I loaded Rad Studio 11 that projects created in 10.4 would no longer run in version 11.
I was happy when they compiled without issue and ran on Windows. On Android however they installed but got into a knot, stalling on the phone and closing on the debugger. They do not even progress as far as the Initialization procedure "Application.Initialize"
The work around was to create a new project in D11 and manually include all the Forms and units and setup all the options, But this is a real pain and prone to errors. All then compiles and runs fine.
My past system has been to open the old project, allow Delphi to do any conversion stuff and save in a new directory. When I found the solution I recalled I had the same issue going from 10.3 to 10.4.
ADUG Forum suggested the SDK files could be fixed by right clicking the Android Target and Reverting System Files to Default and rebuilding but I was not able to achieve a fix by this method. .
"Under the Android target in Project Manager, right-click the Libraries node and click “Revert System Files To Default”, then rebuild."
If this fails I suggest you open the project directory and delete the AndroidManifestTemplate and all of the miscellaneous MyProject.* files except MyProject.dpr then make sure you clear all leftover manifest files, java. classes and object files.