diff --git a/pyproject.toml b/pyproject.toml
index 4d00e8d..10eb547 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,7 +9,7 @@ description = "notifier server for discours.io"
 authors = ["discours.io devteam"]
 
 [tool.poetry.dependencies]
-python = "^3.11"
+python = "^3.9"
 SQLAlchemy = "^2.0.22"
 psycopg2-binary = "^2.9.9"
 redis = {extras = ["hiredis"], version = "^5.0.1"}
@@ -33,7 +33,7 @@ pytest-cov = "^4.1.0"
 
 [tool.black]
 line-length = 120
-target-version = ['py311']
+target-version = ['py39']
 include = '\.pyi?$'
 exclude = '''
 
@@ -75,7 +75,7 @@ reportMissingImports = false
 reportMissingModuleSource = "warning"
 reportImportCycles = "warning"
 maxMemoryForLargeFile = 4096
-pythonVersion = "3.11"
+pythonVersion = "3.9"
 autoImportCompletions = true
 useVirtualEnv = true
 typeCheckingMode = "basic"
@@ -103,7 +103,7 @@ plugins = ["mypy_sqlalchemy.plugin", "strawberry.ext.mypy_plugin"]
 select = ["E4", "E7", "E9", "F"]
 ignore = []
 line-length = 120
-target-version = "py311"
+target-version = "py39"