Deprecate NextStepHandler

aiogram/dispatcher/handler.py

@@ -1,5 +1,6 @@
 from asyncio import Event
 
+from aiogram.utils.deprecated import deprecated
 from .filters import check_filters, CancelFilter
 from .. import types
 
@@ -49,6 +50,7 @@ class Handler:
                     break
 
 
+@deprecated('This handler will be removed soon.')
 class NextStepHandler:
     def __init__(self, dispatcher):
         self.dispatcher = dispatcher