diff --git a/dfaligner/config/__init__.py b/dfaligner/config/__init__.py
index cf82f12..f64b89e 100644
--- a/dfaligner/config/__init__.py
+++ b/dfaligner/config/__init__.py
@@ -1,6 +1,6 @@
 from enum import Enum
 from pathlib import Path
-from typing import Any, Optional
+from typing import Annotated, Any, Optional
 
 from everyvoice.config.preprocessing_config import PreprocessingConfig
 from everyvoice.config.shared_types import (
@@ -17,6 +17,9 @@
 from everyvoice.utils import load_config_from_json_or_yaml_path
 from pydantic import Field, FilePath, ValidationInfo, field_serializer, model_validator
 
+# DFAlignerConfig's latest version number
+LATEST_VERSION: str = "1.0"
+
 
 class DFAlignerExtractionMethod(Enum):
     beam = "beam"
@@ -61,6 +64,14 @@ def convert_extraction_method_enum(
 
 
 class DFAlignerConfig(BaseModelWithContact):
+    VERSION: Annotated[
+        str,
+        Field(
+            default_factory=lambda: LATEST_VERSION,
+            init_var=False,
+        ),
+    ]
+
     # TODO FastSpeech2Config and DFAlignerConfig are almost identical.
     model: DFAlignerModelConfig = Field(
         default_factory=DFAlignerModelConfig,
@@ -108,4 +119,22 @@ def load_config_from_path(path: Path) -> "DFAlignerConfig":
             config = DFAlignerConfig(**config)
         return config
 
+    @model_validator(mode="before")
+    @classmethod
+    def check_and_upgrade_checkpoint(cls, data: Any) -> Any:
+        """
+        Check model's compatibility and possibly upgrade.
+        """
+        ckpt_version = data.get("VERSION", "0.0")
+        if ckpt_version > LATEST_VERSION:
+            raise ValueError(
+                "Your config was created with a newer version of EveryVoice, please update your software."
+            )
+        # Successively convert model checkpoints to newer version.
+        if ckpt_version < "1.0":
+            # Converting to 1.0 just requires setting the VERSION field
+            data["VERSION"] = "1.0"
+
+        return data
+
     # INPUT_TODO: initialize text with union of symbols from dataset