diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 9975878e..94492e3c 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 0.16.5
+current_version = 0.16.6
 tag = True
 tag_name = {new_version}
 commit = True
diff --git a/openapi_core/__init__.py b/openapi_core/__init__.py
index 11184b3d..35ab4e0d 100644
--- a/openapi_core/__init__.py
+++ b/openapi_core/__init__.py
@@ -20,7 +20,7 @@
 
 __author__ = "Artur Maciag"
 __email__ = "maciag.artur@gmail.com"
-__version__ = "0.16.5"
+__version__ = "0.16.6"
 __url__ = "https://github.com/p1c2u/openapi-core"
 __license__ = "BSD 3-Clause License"
 
diff --git a/poetry.lock b/poetry.lock
index b32291e2..3cf50d89 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -530,7 +530,7 @@ setuptools = "*"
 
 [[package]]
 name = "openapi-schema-validator"
-version = "0.4.0"
+version = "0.4.3"
 description = "OpenAPI schema validation for Python"
 category = "main"
 optional = false
@@ -538,11 +538,7 @@ python-versions = ">=3.7.0,<4.0.0"
 
 [package.dependencies]
 jsonschema = ">=4.0.0,<5.0.0"
-
-[package.extras]
-isodate = ["isodate"]
-rfc3339-validator = ["rfc3339-validator"]
-strict-rfc3339 = ["strict-rfc3339"]
+rfc3339-validator = "*"
 
 [[package]]
 name = "openapi-spec-validator"
@@ -804,6 +800,17 @@ urllib3 = ">=1.25.10"
 [package.extras]
 tests = ["coverage (>=6.0.0)", "flake8", "mypy", "pytest (>=7.0.0)", "pytest-asyncio", "pytest-cov", "pytest-httpserver", "types-requests"]
 
+[[package]]
+name = "rfc3339-validator"
+version = "0.1.4"
+description = "A pure python RFC3339 validator"
+category = "main"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
+
+[package.dependencies]
+six = "*"
+
 [[package]]
 name = "rfc3986"
 version = "1.5.0"
@@ -1123,7 +1130,7 @@ starlette = []
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.7.0"
-content-hash = "e5ec69330ace1d6535f46237a0887688df8a933a5490f6f0b0da20d1e1f4d56c"
+content-hash = "cc334cce47b3171b831527cb360f0484209a664b0e87e138bbcdd6ade0964e28"
 
 [metadata.files]
 alabaster = [
@@ -1475,8 +1482,8 @@ nodeenv = [
     {file = "nodeenv-1.7.0.tar.gz", hash = "sha256:e0e7f7dfb85fc5394c6fe1e8fa98131a2473e04311a45afb6508f7cf1836fa2b"},
 ]
 openapi-schema-validator = [
-    {file = "openapi_schema_validator-0.4.0-py3-none-any.whl", hash = "sha256:f1faaae0b1076d6f6bf6ad5d8bb53f49d9cc49621f5e224e2bc121ef76016c04"},
-    {file = "openapi_schema_validator-0.4.0.tar.gz", hash = "sha256:fb591258bbe1e24f381d83cff2e9a1a6fc547936adb46143fdd089f6ea411cc8"},
+    {file = "openapi_schema_validator-0.4.3-py3-none-any.whl", hash = "sha256:f1eff2a7936546a3ce62b88a17d09de93c9bd229cbc43cb696c988a61a382548"},
+    {file = "openapi_schema_validator-0.4.3.tar.gz", hash = "sha256:6940dba9f4906c97078fea6fd9d5a3a3384207db368c4e32f6af6abd7c5c560b"},
 ]
 openapi-spec-validator = [
     {file = "openapi_spec_validator-0.5.2-py3-none-any.whl", hash = "sha256:1f8db08ecbcf4ec8c558d65b65b3b7b428f81da6642f2f163e992ae3e17b229c"},
@@ -1623,6 +1630,10 @@ responses = [
     {file = "responses-0.22.0-py3-none-any.whl", hash = "sha256:dcf294d204d14c436fddcc74caefdbc5764795a40ff4e6a7740ed8ddbf3294be"},
     {file = "responses-0.22.0.tar.gz", hash = "sha256:396acb2a13d25297789a5866b4881cf4e46ffd49cc26c43ab1117f40b973102e"},
 ]
+rfc3339-validator = [
+    {file = "rfc3339_validator-0.1.4-py2.py3-none-any.whl", hash = "sha256:24f6ec1eda14ef823da9e36ec7113124b39c04d50a4d3d3a3c2859577e7791fa"},
+    {file = "rfc3339_validator-0.1.4.tar.gz", hash = "sha256:138a2abdf93304ad60530167e51d2dfb9549521a836871b88d7f4695d0022f6b"},
+]
 rfc3986 = [
     {file = "rfc3986-1.5.0-py2.py3-none-any.whl", hash = "sha256:a86d6e1f5b1dc238b218b012df0aa79409667bb209e58da56d0b94704e712a97"},
     {file = "rfc3986-1.5.0.tar.gz", hash = "sha256:270aaf10d87d0d4e095063c65bf3ddbc6ee3d0b226328ce21e036f946e421835"},
diff --git a/pyproject.toml b/pyproject.toml
index 824a52fc..1ac13d8f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,7 +29,7 @@ ignore_missing_imports = true
 
 [tool.poetry]
 name = "openapi-core"
-version = "0.16.5"
+version = "0.16.6"
 description = "client-side and server-side support for the OpenAPI Specification v3"
 authors = ["Artur Maciag <maciag.artur@gmail.com>"]
 license = "BSD-3-Clause"
diff --git a/tests/unit/unmarshalling/test_validate.py b/tests/unit/unmarshalling/test_validate.py
index 9ad18fa5..4d33ab02 100644
--- a/tests/unit/unmarshalling/test_validate.py
+++ b/tests/unit/unmarshalling/test_validate.py
@@ -384,7 +384,6 @@ def test_string_invalid(self, value, validator_factory):
     @pytest.mark.parametrize(
         "value",
         [
-            b"true",
             "test",
             False,
             1,
@@ -441,7 +440,6 @@ def test_string_format_uuid(self, value, validator_factory):
     @pytest.mark.parametrize(
         "value",
         [
-            b"true",
             "true",
             False,
             1,
@@ -464,7 +462,6 @@ def test_string_format_uuid_invalid(self, value, validator_factory):
     @pytest.mark.parametrize(
         "value",
         [
-            b"true",
             "true",
             False,
             1,
@@ -483,57 +480,6 @@ def test_string_format_datetime_invalid(self, value, validator_factory):
         with pytest.raises(InvalidSchemaValue):
             validator_factory(spec).validate(value)
 
-    @pytest.mark.parametrize(
-        "value",
-        [
-            "1989-01-02T00:00:00Z",
-            "2018-01-02T23:59:59Z",
-        ],
-    )
-    @mock.patch(
-        "openapi_schema_validator._format." "DATETIME_HAS_STRICT_RFC3339", True
-    )
-    @mock.patch(
-        "openapi_schema_validator._format." "DATETIME_HAS_ISODATE", False
-    )
-    def test_string_format_datetime_strict_rfc3339(
-        self, value, validator_factory
-    ):
-        schema = {
-            "type": "string",
-            "format": "date-time",
-        }
-        spec = Spec.from_dict(schema)
-
-        result = validator_factory(spec).validate(value)
-
-        assert result is None
-
-    @pytest.mark.parametrize(
-        "value",
-        [
-            "1989-01-02T00:00:00Z",
-            "2018-01-02T23:59:59Z",
-        ],
-    )
-    @mock.patch(
-        "openapi_schema_validator._format." "DATETIME_HAS_STRICT_RFC3339",
-        False,
-    )
-    @mock.patch(
-        "openapi_schema_validator._format." "DATETIME_HAS_ISODATE", True
-    )
-    def test_string_format_datetime_isodate(self, value, validator_factory):
-        schema = {
-            "type": "string",
-            "format": "date-time",
-        }
-        spec = Spec.from_dict(schema)
-
-        result = validator_factory(spec).validate(value)
-
-        assert result is None
-
     @pytest.mark.parametrize(
         "value",
         [