diff --git a/calendarweek/calendarweek.py b/calendarweek/calendarweek.py
index 538e249fa93228d4c623589f577853efb23d57af..9fe3ffe8abe9d204fd111f51825a8dbcd4e59f95 100644
--- a/calendarweek/calendarweek.py
+++ b/calendarweek/calendarweek.py
@@ -20,28 +20,28 @@ class CalendarWeek:
     def day_names(cls, loc: Optional[str] = None) -> Tuple[str]:
         """ Return a tuple of day names for the selected locale. """
 
-        with calendar.different_localenormalise_locale(loc):
+        with calendar.different_locale(normalise_locale(loc):
             return tuple(calendar.day_name)
 
     @classmethod
     def day_abbrs(cls, loc: Optional[str] = None) -> Tuple[str]:
         """ Return a tuple of day name abbreviations for the selected locale. """
 
-        with calendar.different_localenormalise_locale(loc):
+        with calendar.different_locale(normalise_locale(loc):
             return tuple(calendar.day_abbr)
 
     @classmethod
     def month_names(cls, loc: Optional[str] = None) -> Tuple[str]:
         """ Return a tuple of month names for the selected locale. """
 
-        with calendar.different_localenormalise_locale(loc):
+        with calendar.different_locale(normalise_locale(loc):
             return tuple(calendar.month_name[1:])
 
     @classmethod
     def month_abbrs(cls, loc: Optional[str] = None) -> Tuple[str]:
         """ Return a tuple of month name abbreviations for the selected locale. """
 
-        with calendar.different_localenormalise_locale(loc):
+        with calendar.different_locale(normalise_locale(loc):
             return tuple(calendar.month_abbr[1:])
 
     @classmethod
diff --git a/pyproject.toml b/pyproject.toml
index d1fe0e216d4602ffbbd936ad8f0d80de3c739d97..4e38f2043e75d004d68092191dd839a0e1e1c5da 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "calendarweek"
-version = "0.4.1"
+version = "0.4.2"
 description = "Utilities for working with calendar weeks in Python and Django"
 authors = ["Dominik George <nik@naturalnet.de>", "Jonathan Weth <git@jonathanweth.de>"]
 license = "MIT"