diff --git a/electrum/exchange_rate.py b/electrum/exchange_rate.py
index 5cae92fcb..ed7effaf5 100644
--- a/electrum/exchange_rate.py
+++ b/electrum/exchange_rate.py
@@ -17,7 +17,8 @@ from . import util
 from .bitcoin import COIN
 from .i18n import _
 from .util import (ThreadJob, make_dir, log_exceptions, OldTaskGroup,
-                   make_aiohttp_session, resource_path, EventListener, event_listener, to_decimal)
+                   make_aiohttp_session, resource_path, EventListener, event_listener, to_decimal,
+                   timestamp_to_datetime)
 from .util import NetworkRetryManager
 from .network import Network
 from .simple_config import SimpleConfig
@@ -306,7 +307,7 @@ class CoinCap(ExchangeBase):
         # (and history starts on 2017-03-23)
         history = await self.get_json('api.coincap.io',
                                       '/v2/assets/bitcoin/history?interval=d1&limit=2000')
-        return dict([(datetime.utcfromtimestamp(h['time']/1000).strftime('%Y-%m-%d'), str(h['priceUsd']))
+        return dict([(timestamp_to_datetime(h['time']/1000, utc=True).strftime('%Y-%m-%d'), str(h['priceUsd']))
                      for h in history['data']])
 
 
@@ -354,7 +355,7 @@ class CoinGecko(ExchangeBase):
         history = await self.get_json('api.coingecko.com',
                                       '/api/v3/coins/bitcoin/market_chart?vs_currency=%s&days=max' % ccy)
 
-        return dict([(datetime.utcfromtimestamp(h[0]/1000).strftime('%Y-%m-%d'), str(h[1]))
+        return dict([(timestamp_to_datetime(h[0]/1000, utc=True).strftime('%Y-%m-%d'), str(h[1]))
                      for h in history['prices']])
 
 
@@ -371,7 +372,7 @@ class Bit2C(ExchangeBase):
         history = await self.get_json('bit2c.co.il',
                                       '/Exchanges/BtcNis/KLines?resolution=1D&from=1357034400&to=%s' % int(time.time()))
 
-        return dict([(datetime.utcfromtimestamp(h[0]).strftime('%Y-%m-%d'), str(h[6]))
+        return dict([(timestamp_to_datetime(h[0], utc=True).strftime('%Y-%m-%d'), str(h[6]))
                      for h in history])
 
 
diff --git a/electrum/logging.py b/electrum/logging.py
index 66be956a5..f0c137ba3 100644
--- a/electrum/logging.py
+++ b/electrum/logging.py
@@ -134,7 +134,7 @@ def _configure_file_logging(log_directory: pathlib.Path, *, num_files_keep: int)
 
     _delete_old_logs(log_directory, num_files_keep=num_files_keep)
 
-    timestamp = datetime.datetime.utcnow().strftime("%Y%m%dT%H%M%SZ")
+    timestamp = datetime.datetime.now(datetime.timezone.utc).strftime("%Y%m%dT%H%M%SZ")
     PID = os.getpid()
     _logfile_path = log_directory / f"electrum_log_{timestamp}_{PID}.log"
 
diff --git a/electrum/util.py b/electrum/util.py
index 80ec65fc7..740177fbe 100644
--- a/electrum/util.py
+++ b/electrum/util.py
@@ -26,7 +26,7 @@ import os, sys, re, json
 from collections import defaultdict, OrderedDict
 from typing import (NamedTuple, Union, TYPE_CHECKING, Tuple, Optional, Callable, Any,
                     Sequence, Dict, Generic, TypeVar, List, Iterable, Set, Awaitable)
-from datetime import datetime
+from datetime import datetime, timezone
 import decimal
 from decimal import Decimal
 import traceback
@@ -808,10 +808,13 @@ def quantize_feerate(fee) -> Union[None, Decimal, int]:
     return Decimal(fee).quantize(_feerate_quanta, rounding=decimal.ROUND_HALF_DOWN)
 
 
-def timestamp_to_datetime(timestamp: Union[int, float, None]) -> Optional[datetime]:
+def timestamp_to_datetime(timestamp: Union[int, float, None], *, utc: bool = False) -> Optional[datetime]:
     if timestamp is None:
         return None
-    return datetime.fromtimestamp(timestamp)
+    tz = None
+    if utc:
+        tz = timezone.utc
+    return datetime.fromtimestamp(timestamp, tz=tz)
 
 
 def format_time(timestamp: Union[int, float, None]) -> str:
diff --git a/electrum/x509.py b/electrum/x509.py
index 68cf92b94..424793e5c 100644
--- a/electrum/x509.py
+++ b/electrum/x509.py
@@ -25,10 +25,9 @@
 
 import hashlib
 import time
-from datetime import datetime
 
 from . import util
-from .util import profiler
+from .util import profiler, timestamp_to_datetime
 from .logging import get_logger
 
 
@@ -307,7 +306,7 @@ class X509(object):
         if self.notBefore > now:
             raise CertificateError('Certificate has not entered its valid date range. (%s)' % self.get_common_name())
         if self.notAfter <= now:
-            dt = datetime.utcfromtimestamp(time.mktime(self.notAfter))
+            dt = timestamp_to_datetime(time.mktime(self.notAfter), utc=True)
             raise CertificateError(f'Certificate ({self.get_common_name()}) has expired (at {dt} UTC).')
 
     def getFingerprint(self):