Index: blue-0.8.0/blue/__init__.py
===================================================================
--- blue-0.8.0.orig/blue/__init__.py
+++ blue-0.8.0/blue/__init__.py
@@ -387,8 +387,9 @@ def main():
         'Black', 'Blue'
     )
     # Change the config param callback to support setup.cfg, tox.ini, etc.
-    config_param = black.main.params[21]
-    assert config_param.name == 'config'
+    # the index changed somewhere between black 21.7b and 21.12b
+    cfgidx = {p.name: i for (i, p) in enumerate(black.main.params)}['config']
+    config_param = black.main.params[cfgidx]
     config_param.callback = read_configs
     # Change the version string by adding a redundant Click `version_option`
     # decorator on `black.main`. Fortunately the added `version_option` takes
Index: blue-0.8.0/setup.py
===================================================================
--- blue-0.8.0.orig/setup.py
+++ blue-0.8.0/setup.py
@@ -37,7 +37,7 @@ setup(
     packages=['blue'],
     tests_require=['tox'],
     cmdclass={'test': Tox},
-    install_requires=['black==21.7b0', 'flake8>=3.8'],
+    install_requires=['black>=21.7b0', 'flake8>=3.8'],
     project_urls={
         'Documentation': 'https://blue.readthedocs.io/en/latest',
         'Source': 'https://github.com/grantjenks/blue.git',