Hi,
with this tool can, every time a new app version is created, create a new GUID for Crashlytics.
The new GUID is stored in the "com_crashlytics_build_id.xml" file.
Path of the file: ...\Objects\res\values
#Region Conditional Compilation
#if Release
#CustomBuildAction: 2, my_drive_and_my_folder\CreateCrashlyticsGUID.exe,
#End If
#End Region