diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 373493a6e..9b1bdee9c 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -44,7 +44,7 @@ repos:
 
   - repo: https://github.com/charliermarsh/ruff-pre-commit
     # Ruff version.
-    rev: 'v0.14.14'
+    rev: 'v0.15.0'
     hooks:
       - id: ruff
       - id: ruff-format
diff --git a/freqtrade/enums/candletype.py b/freqtrade/enums/candletype.py
index eb7ae50b8..dddabdb70 100644
--- a/freqtrade/enums/candletype.py
+++ b/freqtrade/enums/candletype.py
@@ -1,7 +1,7 @@
-from enum import Enum
+from enum import StrEnum
 
 
-class CandleType(str, Enum):
+class CandleType(StrEnum):
     """Enum to distinguish candle types"""
 
     SPOT = "spot"
@@ -14,9 +14,6 @@ class CandleType(str, Enum):
     FUNDING_RATE = "funding_rate"
     # BORROW_RATE = "borrow_rate"  # * unimplemented
 
-    def __str__(self):
-        return f"{self.name.lower()}"
-
     @staticmethod
     def from_string(value: str) -> "CandleType":
         if not value:
diff --git a/freqtrade/enums/marginmode.py b/freqtrade/enums/marginmode.py
index f1a4a3a17..69e99b2ea 100644
--- a/freqtrade/enums/marginmode.py
+++ b/freqtrade/enums/marginmode.py
@@ -1,7 +1,7 @@
-from enum import Enum
+from enum import StrEnum
 
 
-class MarginMode(str, Enum):
+class MarginMode(StrEnum):
     """
     Enum to distinguish between
     cross margin/futures margin_mode and
@@ -11,6 +11,3 @@ class MarginMode(str, Enum):
     CROSS = "cross"
     ISOLATED = "isolated"
     NONE = ""
-
-    def __str__(self):
-        return f"{self.value.lower()}"
diff --git a/freqtrade/enums/ordertypevalue.py b/freqtrade/enums/ordertypevalue.py
index 3a253166d..9727887a6 100644
--- a/freqtrade/enums/ordertypevalue.py
+++ b/freqtrade/enums/ordertypevalue.py
@@ -1,6 +1,6 @@
-from enum import Enum
+from enum import StrEnum
 
 
-class OrderTypeValues(str, Enum):
+class OrderTypeValues(StrEnum):
     limit = "limit"
     market = "market"
diff --git a/freqtrade/enums/pricetype.py b/freqtrade/enums/pricetype.py
index f2e3bef23..456c9daad 100644
--- a/freqtrade/enums/pricetype.py
+++ b/freqtrade/enums/pricetype.py
@@ -1,7 +1,7 @@
-from enum import Enum
+from enum import StrEnum
 
 
-class PriceType(str, Enum):
+class PriceType(StrEnum):
     """Enum to distinguish possible trigger prices for stoplosses"""
 
     LAST = "last"
diff --git a/freqtrade/enums/rpcmessagetype.py b/freqtrade/enums/rpcmessagetype.py
index 6fdd788e8..bf7019322 100644
--- a/freqtrade/enums/rpcmessagetype.py
+++ b/freqtrade/enums/rpcmessagetype.py
@@ -1,7 +1,7 @@
-from enum import Enum
+from enum import StrEnum
 
 
-class RPCMessageType(str, Enum):
+class RPCMessageType(StrEnum):
     STATUS = "status"
     WARNING = "warning"
     EXCEPTION = "exception"
@@ -25,21 +25,16 @@ class RPCMessageType(str, Enum):
     NEW_CANDLE = "new_candle"
 
     def __repr__(self):
-        return self.value
-
-    def __str__(self):
+        # TODO: do we still need to overwrite __repr__? Impact needs to be looked at in detail
         return self.value
 
 
 # Enum for parsing requests from ws consumers
-class RPCRequestType(str, Enum):
+class RPCRequestType(StrEnum):
     SUBSCRIBE = "subscribe"
 
     WHITELIST = "whitelist"
     ANALYZED_DF = "analyzed_df"
 
-    def __str__(self):
-        return self.value
-
 
 NO_ECHO_MESSAGES = (RPCMessageType.ANALYZED_DF, RPCMessageType.WHITELIST, RPCMessageType.NEW_CANDLE)
diff --git a/freqtrade/enums/runmode.py b/freqtrade/enums/runmode.py
index f3316629a..ee0f97fb2 100644
--- a/freqtrade/enums/runmode.py
+++ b/freqtrade/enums/runmode.py
@@ -1,7 +1,7 @@
-from enum import Enum
+from enum import StrEnum
 
 
-class RunMode(str, Enum):
+class RunMode(StrEnum):
     """
     Bot running mode (backtest, hyperopt, ...)
     can be "live", "dry-run", "backtest", "hyperopt".
diff --git a/freqtrade/enums/signaltype.py b/freqtrade/enums/signaltype.py
index 267a37ab3..082b9a88a 100644
--- a/freqtrade/enums/signaltype.py
+++ b/freqtrade/enums/signaltype.py
@@ -1,7 +1,7 @@
-from enum import Enum
+from enum import StrEnum
 
 
-class SignalType(Enum):
+class SignalType(StrEnum):
     """
     Enum to distinguish between enter and exit signals
     """
@@ -11,11 +11,8 @@ class SignalType(Enum):
     ENTER_SHORT = "enter_short"
     EXIT_SHORT = "exit_short"
 
-    def __str__(self):
-        return f"{self.name.lower()}"
 
-
-class SignalTagType(Enum):
+class SignalTagType(StrEnum):
     """
     Enum for signal columns
     """
@@ -23,13 +20,7 @@ class SignalTagType(Enum):
     ENTER_TAG = "enter_tag"
     EXIT_TAG = "exit_tag"
 
-    def __str__(self):
-        return f"{self.name.lower()}"
 
-
-class SignalDirection(str, Enum):
+class SignalDirection(StrEnum):
     LONG = "long"
     SHORT = "short"
-
-    def __str__(self):
-        return f"{self.name.lower()}"
diff --git a/freqtrade/enums/tradingmode.py b/freqtrade/enums/tradingmode.py
index a681d60f9..7f025b033 100644
--- a/freqtrade/enums/tradingmode.py
+++ b/freqtrade/enums/tradingmode.py
@@ -1,7 +1,7 @@
-from enum import Enum
+from enum import StrEnum
 
 
-class TradingMode(str, Enum):
+class TradingMode(StrEnum):
     """
     Enum to distinguish between
     spot, margin, futures or any other trading method
@@ -10,6 +10,3 @@ class TradingMode(str, Enum):
     SPOT = "spot"
     MARGIN = "margin"
     FUTURES = "futures"
-
-    def __str__(self):
-        return f"{self.name.lower()}"
diff --git a/freqtrade/exchange/exchange.py b/freqtrade/exchange/exchange.py
index 4ed4a8d20..22b123ea8 100644
--- a/freqtrade/exchange/exchange.py
+++ b/freqtrade/exchange/exchange.py
@@ -207,7 +207,7 @@ class Exchange:
             self._config.get("trading_mode", self._supported_trading_mode_margin_pairs[0][0])
         )
         self.margin_mode: MarginMode = MarginMode(
-            MarginMode(self._config.get("margin_mode"))
+            self._config["margin_mode"]
             if self._config.get("margin_mode")
             else self._supported_trading_mode_margin_pairs[0][1]
         )
diff --git a/freqtrade/misc.py b/freqtrade/misc.py
index e9dba5856..c1fdbc537 100644
--- a/freqtrade/misc.py
+++ b/freqtrade/misc.py
@@ -210,12 +210,12 @@ def remove_entry_exit_signals(dataframe: pd.DataFrame):
 
     :param dataframe: The DataFrame to remove signals from
     """
-    dataframe[SignalType.ENTER_LONG.value] = 0
-    dataframe[SignalType.EXIT_LONG.value] = 0
-    dataframe[SignalType.ENTER_SHORT.value] = 0
-    dataframe[SignalType.EXIT_SHORT.value] = 0
-    dataframe[SignalTagType.ENTER_TAG.value] = None
-    dataframe[SignalTagType.EXIT_TAG.value] = None
+    dataframe[SignalType.ENTER_LONG] = 0
+    dataframe[SignalType.EXIT_LONG] = 0
+    dataframe[SignalType.ENTER_SHORT] = 0
+    dataframe[SignalType.EXIT_SHORT] = 0
+    dataframe[SignalTagType.ENTER_TAG] = None
+    dataframe[SignalTagType.EXIT_TAG] = None
 
     return dataframe
 
diff --git a/freqtrade/persistence/key_value_store.py b/freqtrade/persistence/key_value_store.py
index 0d5a97fa1..310e82b4b 100644
--- a/freqtrade/persistence/key_value_store.py
+++ b/freqtrade/persistence/key_value_store.py
@@ -1,5 +1,5 @@
 from datetime import UTC, datetime
-from enum import Enum
+from enum import StrEnum
 from typing import ClassVar, Literal
 
 from sqlalchemy import String
@@ -11,7 +11,7 @@ from freqtrade.persistence.base import ModelBase, SessionType
 ValueTypes = str | datetime | float | int
 
 
-class ValueTypesEnum(str, Enum):
+class ValueTypesEnum(StrEnum):
     STRING = "str"
     DATETIME = "datetime"
     FLOAT = "float"
diff --git a/freqtrade/plugins/pairlist/IPairList.py b/freqtrade/plugins/pairlist/IPairList.py
index 9cb5d7744..aa5f2c166 100644
--- a/freqtrade/plugins/pairlist/IPairList.py
+++ b/freqtrade/plugins/pairlist/IPairList.py
@@ -5,7 +5,7 @@ PairList Handler base class
 import logging
 from abc import ABC, abstractmethod
 from copy import deepcopy
-from enum import Enum
+from enum import StrEnum
 from typing import Any, Literal, TypedDict
 
 from freqtrade.constants import Config
@@ -58,7 +58,7 @@ PairlistParameter = (
 )
 
 
-class SupportsBacktesting(str, Enum):
+class SupportsBacktesting(StrEnum):
     """
     Enum to indicate if a Pairlist Handler supports backtesting.
     """
diff --git a/freqtrade/strategy/interface.py b/freqtrade/strategy/interface.py
index 935f9dfdd..322f58f4f 100644
--- a/freqtrade/strategy/interface.py
+++ b/freqtrade/strategy/interface.py
@@ -1329,13 +1329,13 @@ class IStrategy(ABC, HyperStrategyMixin):
             return False, False, None
 
         if is_short:
-            enter = latest.get(SignalType.ENTER_SHORT.value, 0) == 1
-            exit_ = latest.get(SignalType.EXIT_SHORT.value, 0) == 1
+            enter = latest.get(SignalType.ENTER_SHORT, 0) == 1
+            exit_ = latest.get(SignalType.EXIT_SHORT, 0) == 1
 
         else:
-            enter = latest.get(SignalType.ENTER_LONG.value, 0) == 1
-            exit_ = latest.get(SignalType.EXIT_LONG.value, 0) == 1
-        exit_tag = latest.get(SignalTagType.EXIT_TAG.value, None)
+            enter = latest.get(SignalType.ENTER_LONG, 0) == 1
+            exit_ = latest.get(SignalType.EXIT_LONG, 0) == 1
+        exit_tag = latest.get(SignalTagType.EXIT_TAG, None)
         # Tags can be None, which does not resolve to False.
         exit_tag = exit_tag if isinstance(exit_tag, str) and exit_tag != "nan" else None
 
@@ -1362,16 +1362,16 @@ class IStrategy(ABC, HyperStrategyMixin):
         if latest is None or latest_date is None:
             return None, None
 
-        enter_long = latest.get(SignalType.ENTER_LONG.value, 0) == 1
-        exit_long = latest.get(SignalType.EXIT_LONG.value, 0) == 1
-        enter_short = latest.get(SignalType.ENTER_SHORT.value, 0) == 1
-        exit_short = latest.get(SignalType.EXIT_SHORT.value, 0) == 1
+        enter_long = latest.get(SignalType.ENTER_LONG, 0) == 1
+        exit_long = latest.get(SignalType.EXIT_LONG, 0) == 1
+        enter_short = latest.get(SignalType.ENTER_SHORT, 0) == 1
+        exit_short = latest.get(SignalType.EXIT_SHORT, 0) == 1
 
         enter_signal: SignalDirection | None = None
         enter_tag: str | None = None
         if enter_long == 1 and not any([exit_long, enter_short]):
             enter_signal = SignalDirection.LONG
-            enter_tag = latest.get(SignalTagType.ENTER_TAG.value, None)
+            enter_tag = latest.get(SignalTagType.ENTER_TAG, None)
         if (
             self.config.get("trading_mode", TradingMode.SPOT) != TradingMode.SPOT
             and self.can_short
@@ -1379,7 +1379,7 @@ class IStrategy(ABC, HyperStrategyMixin):
             and not any([exit_short, enter_long])
         ):
             enter_signal = SignalDirection.SHORT
-            enter_tag = latest.get(SignalTagType.ENTER_TAG.value, None)
+            enter_tag = latest.get(SignalTagType.ENTER_TAG, None)
 
         enter_tag = enter_tag if isinstance(enter_tag, str) and enter_tag != "nan" else None
 
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 6be379720..0bf62751c 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -6,7 +6,7 @@
 -r requirements-freqai-rl.txt
 -r docs/requirements-docs.txt
 
-ruff==0.14.14
+ruff==0.15.0
 mypy==1.19.1
 pre-commit==4.5.1
 pytest==9.0.2
diff --git a/tests/exchange/test_exchange.py b/tests/exchange/test_exchange.py
index a8fbf36af..dabbca655 100644
--- a/tests/exchange/test_exchange.py
+++ b/tests/exchange/test_exchange.py
@@ -6652,7 +6652,7 @@ def test_verify_candle_type_support(default_conf, mocker):
 
     with pytest.raises(
         OperationalException,
-        match=r"Exchange .* does not support fetching premiumindex candles\.",
+        match=r"Exchange .* does not support fetching premiumIndex candles\.",
     ):
         exchange.verify_candle_type_support(CandleType.PREMIUMINDEX)