There is a bug in the Splunk Enterprise Installer for 9.1.1 on Windows. During the upgrade (coming from 8.2.8) it processes the dashboard XML files obvisously looking for statments to change during the upgrade. There seems to be an errorneous conversion of UTF8 files when the upgrade process saves them again on Windows and all special characters like äÄöÖüÜ got eliminated and replaced by special characters across all dashboards by the upgrade. We had to manually check all dashboards after the upgrade.
To be more precise this not only concerns foreing letters, but simply all characters not part of the standard ASCII character list. You will see that after applying the upgrade all dashboard .XML files will have a current modified date.
