Traceback (most recent call last):
  File "picard\config.py", line 477, in run_upgrade_hooks
  File "picard\config_upgrade.py", line 621, in upgrade_to_v3_0_0dev10
AttributeError: 'ImageFormat' object has no attribute 'lower'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "tagger.py", line 12, in <module>
  File "picard\tagger.py", line 1771, in main
  File "picard\tagger.py", line 255, in __init__
  File "picard\config_upgrade.py", line 717, in upgrade_config
  File "picard\config.py", line 479, in run_upgrade_hooks
picard.config.ConfigUpgradeError: Error during config upgrade from version 3.0.0.dev9 to 3.0.0.dev10 using upgrade_to_v3_0_0dev10()