diff --git a/mywebdav/auth.py b/mywebdav/auth.py
index 1b2808b..fe9bbc3 100644
--- a/mywebdav/auth.py
+++ b/mywebdav/auth.py
@@ -1,4 +1,4 @@
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from typing import Optional
 
 from fastapi import Depends, HTTPException, status
@@ -39,9 +39,9 @@ async def authenticate_user(username: str, password: str, two_factor_code: Optio
 def create_access_token(data: dict, expires_delta: Optional[timedelta] = None, two_factor_verified: bool = False):
     to_encode = data.copy()
     if expires_delta:
-        expire = datetime.utcnow() + expires_delta
+        expire = datetime.now(timezone.utc) + expires_delta
     else:
-        expire = datetime.utcnow() + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+        expire = datetime.now(timezone.utc) + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
     to_encode.update({"exp": expire, "2fa_verified": two_factor_verified})
     encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
     return encoded_jwt
diff --git a/mywebdav/billing/invoice_generator.py b/mywebdav/billing/invoice_generator.py
index 2e5982d..86a73c0 100644
--- a/mywebdav/billing/invoice_generator.py
+++ b/mywebdav/billing/invoice_generator.py
@@ -1,4 +1,4 @@
-from datetime import datetime, date, timedelta
+from datetime import datetime, date, timedelta, timezone
 from decimal import Decimal
 from typing import Optional
 from calendar import monthrange
@@ -182,6 +182,6 @@ The MyWebdav Team
     @staticmethod
     async def mark_invoice_paid(invoice: Invoice) -> Invoice:
         invoice.status = "paid"
-        invoice.paid_at = datetime.utcnow()
+        invoice.paid_at = datetime.now(timezone.utc)
         await invoice.save()
         return invoice
diff --git a/mywebdav/billing/models.py b/mywebdav/billing/models.py
index 926430a..40ab5a0 100644
--- a/mywebdav/billing/models.py
+++ b/mywebdav/billing/models.py
@@ -69,7 +69,7 @@ class Invoice(models.Model):
     user = fields.ForeignKeyField("models.User", related_name="invoices")
     invoice_number = fields.CharField(max_length=50, unique=True)
     stripe_invoice_id = fields.CharField(max_length=255, unique=True, null=True)
-    period_start = fields.DateField(index=True)
+    period_start = fields.DateField(db_index=True)
     period_end = fields.DateField()
     subtotal = fields.DecimalField(max_digits=10, decimal_places=4)
     tax = fields.DecimalField(max_digits=10, decimal_places=4, default=0)
diff --git a/mywebdav/billing/usage_tracker.py b/mywebdav/billing/usage_tracker.py
index 598c57f..f110d29 100644
--- a/mywebdav/billing/usage_tracker.py
+++ b/mywebdav/billing/usage_tracker.py
@@ -1,5 +1,5 @@
 import uuid
-from datetime import datetime, date
+from datetime import datetime, date, timezone
 from decimal import Decimal
 from typing import Optional
 from tortoise.transactions import in_transaction
@@ -15,7 +15,7 @@ class UsageTracker:
         resource_id: int = None,
         metadata: dict = None
     ):
-        idempotency_key = f"storage_{user.id}_{datetime.utcnow().timestamp()}_{uuid.uuid4().hex[:8]}"
+        idempotency_key = f"storage_{user.id}_{datetime.now(timezone.utc).timestamp()}_{uuid.uuid4().hex[:8]}"
 
         await UsageRecord.create(
             user=user,
@@ -37,7 +37,7 @@ class UsageTracker:
         metadata: dict = None
     ):
         record_type = f"bandwidth_{direction}"
-        idempotency_key = f"{record_type}_{user.id}_{datetime.utcnow().timestamp()}_{uuid.uuid4().hex[:8]}"
+        idempotency_key = f"{record_type}_{user.id}_{datetime.now(timezone.utc).timestamp()}_{uuid.uuid4().hex[:8]}"
 
         await UsageRecord.create(
             user=user,
diff --git a/mywebdav/main.py b/mywebdav/main.py
index 3d0352e..5e7a40d 100644
--- a/mywebdav/main.py
+++ b/mywebdav/main.py
@@ -86,7 +86,7 @@ async def http_exception_handler(request: Request, exc: HTTPException):
     logger.error(f"HTTPException: {exc.status_code} - {exc.detail} for URL: {request.url}")
     return JSONResponse(
         status_code=exc.status_code,
-        content=ErrorResponse(code=exc.status_code, message=exc.detail).dict(),
+        content=ErrorResponse(code=exc.status_code, message=exc.detail).model_dump(),
     )
 
 
diff --git a/mywebdav/schemas.py b/mywebdav/schemas.py
index b956f54..9eb52b9 100644
--- a/mywebdav/schemas.py
+++ b/mywebdav/schemas.py
@@ -1,5 +1,5 @@
 from datetime import datetime
-from pydantic import BaseModel, EmailStr
+from pydantic import BaseModel, EmailStr, ConfigDict
 from typing import Optional, List
 from tortoise.contrib.pydantic import pydantic_model_creator
 
@@ -58,8 +58,7 @@ class TeamOut(BaseModel):
     owner_id: int
     created_at: datetime
 
-    class Config:
-        from_attributes = True
+    model_config = ConfigDict(from_attributes=True)
 
 class ActivityOut(BaseModel):
     id: int
@@ -70,8 +69,7 @@ class ActivityOut(BaseModel):
     ip_address: Optional[str] = None
     timestamp: datetime
 
-    class Config:
-        from_attributes = True
+    model_config = ConfigDict(from_attributes=True)
 
 class FileRequestCreate(BaseModel):
     title: str
@@ -90,8 +88,7 @@ class FileRequestOut(BaseModel):
     expires_at: Optional[datetime] = None
     is_active: bool
 
-    class Config:
-        from_attributes = True
+    model_config = ConfigDict(from_attributes=True)
 
 from mywebdav.models import Folder, File, Share, FileVersion
 
diff --git a/tests/conftest.py b/tests/conftest.py
index a4997b7..7d6fdc9 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,4 +1,5 @@
 import pytest
+import pytest_asyncio
 import asyncio
 from tortoise import Tortoise
 
@@ -22,7 +23,7 @@ def event_loop():
     yield loop
     loop.close()
 
-@pytest.fixture(scope="session", autouse=True)
+@pytest_asyncio.fixture(scope="session", autouse=True)
 async def cleanup_db():
     yield
     await Tortoise.close_connections()