diff --git a/.github/actions/setup-conda/action.yml b/.github/actions/setup-conda/action.yml
index ceeebfcd1c90c..e31fed120267a 100644
--- a/.github/actions/setup-conda/action.yml
+++ b/.github/actions/setup-conda/action.yml
@@ -9,6 +9,8 @@ runs:
     - name: Install ${{ inputs.environment-file }}
       uses: mamba-org/setup-micromamba@v1
       with:
+        # Pinning to avoid 2.0 failures
+        micromamba-version: '1.5.10-0'
         environment-file: ${{ inputs.environment-file }}
         environment-name: test
         condarc-file: ci/.condarc
diff --git a/.github/workflows/code-checks.yml b/.github/workflows/code-checks.yml
index f908d1e572ab1..dacf740e5d4d8 100644
--- a/.github/workflows/code-checks.yml
+++ b/.github/workflows/code-checks.yml
@@ -4,11 +4,11 @@ on:
   push:
     branches:
       - main
-      - 2.2.x
+      - 2.3.x
   pull_request:
     branches:
       - main
-      - 2.2.x
+      - 2.3.x
 
 env:
   ENV_FILE: environment.yml
diff --git a/.github/workflows/docbuild-and-upload.yml b/.github/workflows/docbuild-and-upload.yml
index e470b181772ed..3abe9c92bcefa 100644
--- a/.github/workflows/docbuild-and-upload.yml
+++ b/.github/workflows/docbuild-and-upload.yml
@@ -4,13 +4,13 @@ on:
   push:
     branches:
       - main
-      - 2.2.x
+      - 2.3.x
     tags:
       - '*'
   pull_request:
     branches:
       - main
-      - 2.2.x
+      - 2.3.x
 
 env:
   ENV_FILE: environment.yml
diff --git a/.github/workflows/package-checks.yml b/.github/workflows/package-checks.yml
index 7c1da5678a2aa..e1be5659bbd9a 100644
--- a/.github/workflows/package-checks.yml
+++ b/.github/workflows/package-checks.yml
@@ -4,11 +4,11 @@ on:
   push:
     branches:
       - main
-      - 2.2.x
+      - 2.3.x
   pull_request:
     branches:
       - main
-      - 2.2.x
+      - 2.3.x
     types: [ labeled, opened, synchronize, reopened ]
 
 permissions:
diff --git a/.github/workflows/unit-tests.yml b/.github/workflows/unit-tests.yml
index ad63908e4682d..b54fe8f044c78 100644
--- a/.github/workflows/unit-tests.yml
+++ b/.github/workflows/unit-tests.yml
@@ -4,11 +4,11 @@ on:
   push:
     branches:
       - main
-      - 2.2.x
+      - 2.3.x
   pull_request:
     branches:
       - main
-      - 2.2.x
+      - 2.3.x
     paths-ignore:
       - "doc/**"
       - "web/**"
diff --git a/pandas/_testing/contexts.py b/pandas/_testing/contexts.py
index eb6e4a917889a..48616ee134582 100644
--- a/pandas/_testing/contexts.py
+++ b/pandas/_testing/contexts.py
@@ -78,14 +78,15 @@ def set_timezone(tz: str) -> Generator[None, None, None]:
     import time
 
     def setTZ(tz) -> None:
-        if tz is None:
-            try:
-                del os.environ["TZ"]
-            except KeyError:
-                pass
-        else:
-            os.environ["TZ"] = tz
-            time.tzset()
+        if hasattr(time, "tzset"):
+            if tz is None:
+                try:
+                    del os.environ["TZ"]
+                except KeyError:
+                    pass
+            else:
+                os.environ["TZ"] = tz
+                time.tzset()
 
     orig_tz = os.environ.get("TZ")
     setTZ(tz)
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index 259e969112dd7..2f448bf249a2e 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -1218,7 +1218,7 @@ def _replace_coerce(
                     putmask_inplace(nb.values, mask, value)
                     return [nb]
                 if using_cow:
-                    return [self]
+                    return [self.copy(deep=False)]
                 return [self] if inplace else [self.copy()]
             return self.replace(
                 to_replace=to_replace,
diff --git a/pandas/tests/copy_view/test_replace.py b/pandas/tests/copy_view/test_replace.py
index 6d16bc3083883..0beac439fbb58 100644
--- a/pandas/tests/copy_view/test_replace.py
+++ b/pandas/tests/copy_view/test_replace.py
@@ -384,6 +384,15 @@ def test_replace_list_none(using_copy_on_write):
 
     assert not np.shares_memory(get_array(df, "a"), get_array(df2, "a"))
 
+    # replace multiple values that don't actually replace anything with None
+    # https://github.com/pandas-dev/pandas/issues/59770
+    df3 = df.replace(["d", "e", "f"], value=None)
+    tm.assert_frame_equal(df3, df_orig)
+    if using_copy_on_write:
+        assert tm.shares_memory(get_array(df, "a"), get_array(df3, "a"))
+    else:
+        assert not tm.shares_memory(get_array(df, "a"), get_array(df3, "a"))
+
 
 def test_replace_list_none_inplace_refs(using_copy_on_write, warn_copy_on_write):
     df = DataFrame({"a": ["a", "b", "c"]})
diff --git a/pandas/tests/tslibs/test_parsing.py b/pandas/tests/tslibs/test_parsing.py
index d8f23156bd4d4..fb05a57056a83 100644
--- a/pandas/tests/tslibs/test_parsing.py
+++ b/pandas/tests/tslibs/test_parsing.py
@@ -17,6 +17,7 @@
 from pandas._libs.tslibs.parsing import parse_datetime_string_with_reso
 from pandas.compat import (
     ISMUSL,
+    is_platform_arm,
     is_platform_windows,
 )
 import pandas.util._test_decorators as td
@@ -26,7 +27,7 @@
 
 
 @pytest.mark.skipif(
-    is_platform_windows() or ISMUSL,
+    is_platform_windows() or ISMUSL or is_platform_arm(),
     reason="TZ setting incorrect on Windows and MUSL Linux",
 )
 def test_parsing_tzlocal_deprecated():