diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index b995b7f..674760f 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -25,6 +25,7 @@ jobs:
         - '3.11'
         - '3.12'
         - '3.13'
+        - '3.14-dev'
 
     steps:
     - name: "🗃 Cache"
diff --git a/pure_protobuf/descriptors/record.py b/pure_protobuf/descriptors/record.py
index eda3322..245c72f 100644
--- a/pure_protobuf/descriptors/record.py
+++ b/pure_protobuf/descriptors/record.py
@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-from collections.abc import ByteString, Mapping
 from dataclasses import dataclass
 from enum import IntEnum
 from types import GenericAlias
@@ -71,7 +70,7 @@ class RecordDescriptor(Generic[RecordT]):
     merge: Merge[RecordT] = MergeLastOneWins()
     """Merge two values of the same field from different messages. Only called in a message merger."""
 
-    __PREDEFINED__: ClassVar[Mapping[Any, RecordDescriptor]]
+    __PREDEFINED__: ClassVar[dict[Any, RecordDescriptor]]
     """Pre-defined descriptors for primitive types."""
 
     @classmethod
@@ -176,7 +175,6 @@ def _from_inner_type_hint(
     bool: BOOL_DESCRIPTOR,
     bytes: BYTES_DESCRIPTOR,
     bytearray: BYTES_DESCRIPTOR,
-    ByteString: BYTES_DESCRIPTOR,
     fixed32: UNSIGNED_INT32_DESCRIPTOR,
     fixed64: UNSIGNED_INT64_DESCRIPTOR,
     float: FLOAT_DESCRIPTOR,
@@ -206,3 +204,10 @@ def _from_inner_type_hint(
         read=ReadMaybePacked[int](ReadCallback(ReadZigZagVarint()), WireType.VARINT),
     ),
 }
+
+try:
+    from collections.abc import ByteString
+except ImportError:
+    pass
+else:
+    RecordDescriptor.__PREDEFINED__[ByteString] = BYTES_DESCRIPTOR
diff --git a/pyproject.toml b/pyproject.toml
index 604e4e1..c0c6fe7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -95,7 +95,7 @@ exclude_lines = [
 
 [tool.black]
 line-length = 120
-target-version = ["py39", "py310", "py311", "py312", "py313"]
+target-version = ["py39", "py310", "py311", "py312", "py313", "py314"]
 
 [tool.ruff]
 line-length = 120
@@ -148,9 +148,7 @@ ignore = [
     "PT013",
     "RET505",
     "TRY003",
-    "UP006",  # 3.9
     "UP007",  # 3.10
-    "UP033",  # 3.9
 ]
 
 [tool.ruff.lint.per-file-ignores]