diff --git a/pyproject.toml b/pyproject.toml
index 101babb..1047690 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ dependencies = [
     "httpx",
     "pydantic",
     "multidict",
-    "circuit-breaker-box",
+    "circuit-breaker-box>=0.3.9,<0.4",
 ]
 version = "0"
 authors = [{ name = "community-of-python" }]
@@ -71,6 +71,7 @@ ignore = [
     "D213",   # "multi-line-summary-second-line" conflicting with D212
     "COM812", # flake8-commas "Trailing comma missing"
     "ISC001", # flake8-implicit-str-concat
+    "CPY001", # flake8-copyright "Missing copyright notice at top of file"
 ]
 isort.lines-after-imports = 2
 isort.no-lines-before = ["standard-library", "local-folder"]