diff --git a/.sync_state b/.sync_state
index ae6ee89..86ad410 100644
--- a/.sync_state
+++ b/.sync_state
@@ -1 +1 @@
-5b8bbf4e6347642058bb0dda68779cf761e9775d
+c901017e6119fd37d844930047403bab1163363e
diff --git a/requirements-dev.lock b/requirements-dev.lock
index 8460e60..f459af0 100644
--- a/requirements-dev.lock
+++ b/requirements-dev.lock
@@ -88,9 +88,9 @@ pluggy==1.5.0
 propcache==0.3.1
     # via aiohttp
     # via yarl
-pydantic==2.10.3
+pydantic==2.11.9
     # via lmnt
-pydantic-core==2.27.1
+pydantic-core==2.33.2
     # via pydantic
 pygments==2.18.0
     # via rich
@@ -126,6 +126,9 @@ typing-extensions==4.12.2
     # via pydantic
     # via pydantic-core
     # via pyright
+    # via typing-inspection
+typing-inspection==0.4.1
+    # via pydantic
 virtualenv==20.24.5
     # via nox
 websockets==15.0.1
diff --git a/requirements.lock b/requirements.lock
index 36a1dbe..0ca15f4 100644
--- a/requirements.lock
+++ b/requirements.lock
@@ -55,9 +55,9 @@ multidict==6.4.4
 propcache==0.3.1
     # via aiohttp
     # via yarl
-pydantic==2.10.3
+pydantic==2.11.9
     # via lmnt
-pydantic-core==2.27.1
+pydantic-core==2.33.2
     # via pydantic
 sniffio==1.3.0
     # via anyio
@@ -68,6 +68,9 @@ typing-extensions==4.12.2
     # via multidict
     # via pydantic
     # via pydantic-core
+    # via typing-inspection
+typing-inspection==0.4.1
+    # via pydantic
 websockets==15.0.1
     # via lmnt
 yarl==1.20.0
diff --git a/src/lmnt/_models.py b/src/lmnt/_models.py
index 3a6017e..6a3cd1d 100644
--- a/src/lmnt/_models.py
+++ b/src/lmnt/_models.py
@@ -256,7 +256,7 @@ def model_dump(
             mode: Literal["json", "python"] | str = "python",
             include: IncEx | None = None,
             exclude: IncEx | None = None,
-            by_alias: bool = False,
+            by_alias: bool | None = None,
             exclude_unset: bool = False,
             exclude_defaults: bool = False,
             exclude_none: bool = False,
@@ -264,6 +264,7 @@ def model_dump(
             warnings: bool | Literal["none", "warn", "error"] = True,
             context: dict[str, Any] | None = None,
             serialize_as_any: bool = False,
+            fallback: Callable[[Any], Any] | None = None,
         ) -> dict[str, Any]:
             """Usage docs: https://docs.pydantic.dev/2.4/concepts/serialization/#modelmodel_dump
 
@@ -295,10 +296,12 @@ def model_dump(
                 raise ValueError("context is only supported in Pydantic v2")
             if serialize_as_any != False:
                 raise ValueError("serialize_as_any is only supported in Pydantic v2")
+            if fallback is not None:
+                raise ValueError("fallback is only supported in Pydantic v2")
             dumped = super().dict(  # pyright: ignore[reportDeprecated]
                 include=include,
                 exclude=exclude,
-                by_alias=by_alias,
+                by_alias=by_alias if by_alias is not None else False,
                 exclude_unset=exclude_unset,
                 exclude_defaults=exclude_defaults,
                 exclude_none=exclude_none,
@@ -313,13 +316,14 @@ def model_dump_json(
             indent: int | None = None,
             include: IncEx | None = None,
             exclude: IncEx | None = None,
-            by_alias: bool = False,
+            by_alias: bool | None = None,
             exclude_unset: bool = False,
             exclude_defaults: bool = False,
             exclude_none: bool = False,
             round_trip: bool = False,
             warnings: bool | Literal["none", "warn", "error"] = True,
             context: dict[str, Any] | None = None,
+            fallback: Callable[[Any], Any] | None = None,
             serialize_as_any: bool = False,
         ) -> str:
             """Usage docs: https://docs.pydantic.dev/2.4/concepts/serialization/#modelmodel_dump_json
@@ -348,11 +352,13 @@ def model_dump_json(
                 raise ValueError("context is only supported in Pydantic v2")
             if serialize_as_any != False:
                 raise ValueError("serialize_as_any is only supported in Pydantic v2")
+            if fallback is not None:
+                raise ValueError("fallback is only supported in Pydantic v2")
             return super().json(  # type: ignore[reportDeprecated]
                 indent=indent,
                 include=include,
                 exclude=exclude,
-                by_alias=by_alias,
+                by_alias=by_alias if by_alias is not None else False,
                 exclude_unset=exclude_unset,
                 exclude_defaults=exclude_defaults,
                 exclude_none=exclude_none,