diff --git a/pynamodb/attributes.py b/pynamodb/attributes.py
index 3c0f197..36a4e8b 100644
--- a/pynamodb/attributes.py
+++ b/pynamodb/attributes.py
@@ -362,12 +362,9 @@ class BinaryAttribute(Attribute[bytes]):
 
     def deserialize(self, value):
         """
-        Returns a decoded string from base64
+        Returns a decoded byte string from a base64 encoded value
         """
-        try:
-            return b64decode(value.decode(DEFAULT_ENCODING))
-        except AttributeError:
-            return b64decode(value)
+        return b64decode(value)
 
 
 class BinarySetAttribute(SetMixin, Attribute[Set[bytes]]):
@@ -439,15 +436,6 @@ class UnicodeAttribute(Attribute[str]):
     """
     attr_type = STRING
 
-    def serialize(self, value):
-        """
-        Returns a unicode string
-        """
-        if value is None or not len(value):
-            return None
-        else:
-            return value
-
 
 class JSONAttribute(Attribute[Any]):
     """

Empty String/Binary values support?
DynamoDB recently supported empty values for _non-key_ String/Binary attributes.

Though PynamoDB currently supports empty value as null (None), 
does PynamoDB have any plans to support this new feature of DynamoDB?
diff --git a/tests/test_attributes.py b/tests/test_attributes.py
index e39527b..5eb3400 100644
--- a/tests/test_attributes.py
+++ b/tests/test_attributes.py
@@ -54,7 +54,7 @@ class CustomAttrMap(MapAttribute):
 
 class DefaultsMap(MapAttribute):
     map_field = MapAttribute(default={})
-    string_field = UnicodeAttribute(null=True)
+    string_set_field = UnicodeSetAttribute(null=True)
 
 
 class TestAttributeDescriptor:
@@ -378,7 +378,7 @@ class TestUnicodeAttribute:
         """
         attr = UnicodeAttribute()
         assert attr.serialize('foo') == 'foo'
-        assert attr.serialize('') is None
+        assert attr.serialize('') == ''
         assert attr.serialize(None) is None
 
     def test_unicode_deserialize(self):
@@ -388,6 +388,8 @@ class TestUnicodeAttribute:
         attr = UnicodeAttribute()
         assert attr.deserialize('foo') == 'foo'
         assert attr.deserialize(u'foo') == 'foo'
+        assert attr.deserialize('') == ''
+        assert attr.deserialize(None) is None
 
     def test_unicode_set_serialize(self):
         """
@@ -622,7 +624,7 @@ class TestMapAttribute:
 
     def test_null_attribute_map_after_serialization(self):
         null_attribute = {
-            'string_field': '',
+            'string_set_field': {},
         }
         attr = DefaultsMap()
         serialized = attr.serialize(null_attribute)

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest pytest-cov pytest-xdist pytest-mock pytest-asyncio
apt-get update apt-get install -y gcc make sudo
3.9
requirements/base.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
botocore==1.37.23
coverage==7.8.0
exceptiongroup==1.2.2
execnet==2.1.1
iniconfig==2.1.0
jmespath==1.0.1
packaging==24.2
pluggy==1.5.0
-e git+https://github.com/pynamodb/PynamoDB.git@d7e799e9f8ac8bfdc378f347aa82b4f6815b148c#egg=pynamodb
pytest==8.3.5
pytest-asyncio==0.26.0
pytest-cov==6.0.0
pytest-mock==3.14.0
pytest-xdist==3.6.1
python-dateutil==2.9.0.post0
six==1.17.0
tomli==2.2.1
typing_extensions==4.13.0
urllib3==1.26.20

name: PynamoDB
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=3.0.16=h5eee18b_0
  - pip=25.0=py39h06a4308_0
  - python=3.9.21=he870216_1
  - readline=8.2=h5eee18b_0
  - setuptools=75.8.0=py39h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - tzdata=2025a=h04d1e81_0
  - wheel=0.45.1=py39h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - botocore==1.37.23
      - coverage==7.8.0
      - exceptiongroup==1.2.2
      - execnet==2.1.1
      - iniconfig==2.1.0
      - jmespath==1.0.1
      - packaging==24.2
      - pluggy==1.5.0
      - pytest==8.3.5
      - pytest-asyncio==0.26.0
      - pytest-cov==6.0.0
      - pytest-mock==3.14.0
      - pytest-xdist==3.6.1
      - python-dateutil==2.9.0.post0
      - six==1.17.0
      - tomli==2.2.1
      - typing-extensions==4.13.0
      - urllib3==1.26.20
prefix: /opt/conda/envs/PynamoDB

tests/test_attributes.py::TestUnicodeAttribute::test_unicode_serialize
tests/test_attributes.py::TestAttributeDescriptor::test_binary_attr tests/test_attributes.py::TestAttributeDescriptor::test_binary_set_attr tests/test_attributes.py::TestAttributeDescriptor::test_number_attr tests/test_attributes.py::TestAttributeDescriptor::test_number_set_attr tests/test_attributes.py::TestAttributeDescriptor::test_unicode_attr tests/test_attributes.py::TestAttributeDescriptor::test_unicode_set_attr tests/test_attributes.py::TestAttributeDescriptor::test_datetime_attr tests/test_attributes.py::TestAttributeDescriptor::test_bool_attr tests/test_attributes.py::TestAttributeDescriptor::test_json_attr
tests/test_attributes.py::TestUTCDateTimeAttribute::test_utc_datetime_attribute tests/test_attributes.py::TestUTCDateTimeAttribute::test_utc_date_time_deserialize tests/test_attributes.py::TestUTCDateTimeAttribute::test_dateutil_parser_fallback tests/test_attributes.py::TestUTCDateTimeAttribute::test_utc_date_time_deserialize_parse_args tests/test_attributes.py::TestUTCDateTimeAttribute::test_utc_date_time_serialize tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_roundtrips tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_no_microseconds tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2.47-01-06T08:21:00.0+0000] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06T08:21:00.+0000] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06T08:21:00.0] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06 tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[abcd-01-06T08:21:00.0+0000] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-ab-06T08:21:00.0+0000] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-abT08:21:00.0+0000] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06Tab:21:00.0+0000] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06T08:ab:00.0+0000_0] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06T08:ab:00.0+0000_1] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06T08:21:00.a+0000] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06T08:21:00.0.1+0000] tests/test_attributes.py::TestUTCDateTimeAttribute::test__fast_parse_utc_datestring_invalid_input[2047-01-06T08:21:00.0+00000] tests/test_attributes.py::TestBinaryAttribute::test_binary_attribute tests/test_attributes.py::TestBinaryAttribute::test_binary_round_trip tests/test_attributes.py::TestBinaryAttribute::test_binary_serialize tests/test_attributes.py::TestBinaryAttribute::test_binary_deserialize tests/test_attributes.py::TestBinaryAttribute::test_binary_set_serialize tests/test_attributes.py::TestBinaryAttribute::test_binary_set_round_trip tests/test_attributes.py::TestBinaryAttribute::test_binary_set_deserialize tests/test_attributes.py::TestBinaryAttribute::test_binary_set_attribute tests/test_attributes.py::TestNumberAttribute::test_number_attribute tests/test_attributes.py::TestNumberAttribute::test_number_serialize tests/test_attributes.py::TestNumberAttribute::test_number_deserialize tests/test_attributes.py::TestNumberAttribute::test_number_set_deserialize tests/test_attributes.py::TestNumberAttribute::test_number_set_serialize tests/test_attributes.py::TestNumberAttribute::test_number_set_attribute tests/test_attributes.py::TestUnicodeAttribute::test_unicode_attribute tests/test_attributes.py::TestUnicodeAttribute::test_unicode_deserialize tests/test_attributes.py::TestUnicodeAttribute::test_unicode_set_serialize tests/test_attributes.py::TestUnicodeAttribute::test_round_trip_unicode_set tests/test_attributes.py::TestUnicodeAttribute::test_unicode_set_deserialize tests/test_attributes.py::TestUnicodeAttribute::test_unicode_set_attribute tests/test_attributes.py::TestBooleanAttribute::test_boolean_attribute tests/test_attributes.py::TestBooleanAttribute::test_boolean_serialize tests/test_attributes.py::TestBooleanAttribute::test_boolean_deserialize tests/test_attributes.py::TestTTLAttribute::test_default_and_default_for_new tests/test_attributes.py::TestTTLAttribute::test_timedelta_ttl tests/test_attributes.py::TestTTLAttribute::test_datetime_naive_ttl tests/test_attributes.py::TestTTLAttribute::test_datetime_with_tz_ttl tests/test_attributes.py::TestTTLAttribute::test_ttl_attribute_wrong_type tests/test_attributes.py::TestTTLAttribute::test_serialize_timedelta tests/test_attributes.py::TestTTLAttribute::test_serialize_none tests/test_attributes.py::TestTTLAttribute::test_serialize_deserialize tests/test_attributes.py::TestJSONAttribute::test_quoted_json tests/test_attributes.py::TestJSONAttribute::test_json_attribute tests/test_attributes.py::TestJSONAttribute::test_json_serialize tests/test_attributes.py::TestJSONAttribute::test_json_deserialize tests/test_attributes.py::TestJSONAttribute::test_control_chars tests/test_attributes.py::TestMapAttribute::test_attribute_children tests/test_attributes.py::TestMapAttribute::test_null_attribute_raw_map tests/test_attributes.py::TestMapAttribute::test_null_attribute_subclassed_map tests/test_attributes.py::TestMapAttribute::test_null_attribute_map_after_serialization tests/test_attributes.py::TestMapAttribute::test_map_of_map tests/test_attributes.py::TestMapAttribute::test_map_overridden_attrs_accessors tests/test_attributes.py::TestMapAttribute::test_map_overridden_attrs_serialize tests/test_attributes.py::TestMapAttribute::test_additional_attrs_deserialize tests/test_attributes.py::TestMapAttribute::test_defaults tests/test_attributes.py::TestMapAttribute::test_raw_set_attr tests/test_attributes.py::TestMapAttribute::test_raw_set_item tests/test_attributes.py::TestMapAttribute::test_raw_map_from_dict tests/test_attributes.py::TestMapAttribute::test_raw_map_access tests/test_attributes.py::TestMapAttribute::test_raw_map_iter tests/test_attributes.py::TestMapAttribute::test_raw_map_json_serialize tests/test_attributes.py::TestMapAttribute::test_typed_and_raw_map_json_serialize tests/test_attributes.py::TestMapAttribute::test_json_serialize tests/test_attributes.py::TestMapAttribute::test_serialize_datetime tests/test_attributes.py::TestMapAttribute::test_complex_map_accessors tests/test_attributes.py::TestMapAttribute::test_attribute_paths_subclassing tests/test_attributes.py::TestMapAttribute::test_attribute_paths_wrapping tests/test_attributes.py::TestValueDeserialize::test__get_value_for_deserialize tests/test_attributes.py::TestValueDeserialize::test__get_value_for_deserialize_null tests/test_attributes.py::TestMapAndListAttribute::test_map_of_list tests/test_attributes.py::TestMapAndListAttribute::test_map_of_list_of_map tests/test_attributes.py::TestMapAndListAttribute::test_list_of_map_with_of tests/test_attributes.py::TestMapAndListAttribute::test_list_of_map_with_of_and_custom_attribute tests/test_attributes.py::TestVersionAttribute::test_serialize tests/test_attributes.py::TestVersionAttribute::test_deserialize
pynamodb/attributes.py
pynamodb/attributes.py