task: metadata: install: pip install -e .[all]
patch: diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index d12ede3..0931412 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -64,7 +64,14 @@ repos:
       - id: cov-check
         name: Coverage
         language: system
-        entry: pytest -v --cov=arta --cov-fail-under=90
+        entry: coverage report -m --fail-under=90
+        types: [python]
+        pass_filenames: false
+        always_run: true
+      - id: cov-erase
+        name: Coverage - Erase
+        language: system
+        entry: coverage erase
         types: [python]
         pass_filenames: false
         always_run: true
diff --git a/pyproject.toml b/pyproject.toml
index cc6b949..ccfa73d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -93,3 +93,21 @@ exclude = ["tests/*"]
 
 [tool.ruff.format]
 docstring-code-format = true
+
+[tool.coverage.paths]
+source = [
+    "src/arta",
+    "*/.tox/*/lib/python*/site-packages/arta",
+    "*/.tox/pypy*/site-packages/arta",
+    "*/.tox\\*\\Lib\\site-packages\\arta",
+    "*/src/arta",
+    "*\\src\\arta"]
+
+[tool.coverage.run]
+branch = true
+parallel = false
+source = ["arta"]
+omit = ["*/tests/*"]
+
+[tool.coverage.report]
+omit = ["tests"]
diff --git a/src/arta/_engine.py b/src/arta/_engine.py
index 21e8012..462e7a9 100644
--- a/src/arta/_engine.py
+++ b/src/arta/_engine.py
@@ -87,7 +87,8 @@ class RulesEngine:
         # Initialize directly with a rules dict
         if rules_dict is not None:
             # Data validation
-            RulesDict.parse_obj(rules_dict)
+            # RulesDict.parse_obj(rules_dict)
+            RulesDict.model_validate(rules_dict)
 
             # Edge cases data validation
             if not isinstance(rules_dict, dict):
@@ -104,9 +105,8 @@ class RulesEngine:
                 # Load config in attribute
                 config_dict = load_config(config_path)
 
-            if config_dict is not None:
-                # Data validation
-                config: Configuration = Configuration(**config_dict)
+            # Data validation
+            config: Configuration = Configuration.model_validate(config_dict)
 
             if config.parsing_error_strategy is not None:
                 # Set parsing error handling strategy from config
@@ -125,7 +125,7 @@ class RulesEngine:
             # Dictionary of condition instances (k: condition id, v: instance), built from config data
             if len(std_condition_functions) > 0:
                 std_condition_instances = self._build_std_conditions(
-                    config=config.dict(), condition_functions_dict=std_condition_functions
+                    config=config.model_dump(), condition_functions_dict=std_condition_functions
                 )
 
             # User-defined/custom conditions
@@ -150,7 +150,7 @@ class RulesEngine:
             self.rules = self._build_rules(
                 std_condition_instances=std_condition_instances,
                 action_functions=action_functions,
-                config=config.dict(),
+                config=config.model_dump(),
                 factory_mapping_classes=factory_mapping_classes,
             )
 
@@ -288,9 +288,9 @@ class RulesEngine:
         Return a dictionary of Rule instances built from the configuration.
 
         Args:
-            rule_sets: Sets of rules to be loaded in the Rules Engine (as needed by further uses).
+            # rule_sets: Sets of rules to be loaded in the Rules Engine (as needed by further uses).
             std_condition_instances: Dictionary of condition instances (k: condition id, v: StandardCondition instance)
-            actions_dict: Dictionary of action functions (k: action name, v: Callable)
+            action_functions: Dictionary of action functions (k: action name, v: Callable)
             config: Dictionary of the imported configuration from yaml files.
             factory_mapping_classes: A mapping dictionary (k: condition conf. key, v: custom class object)
 
diff --git a/src/arta/models.py b/src/arta/models.py
index d3044a9..0a258a3 100644
--- a/src/arta/models.py
+++ b/src/arta/models.py
@@ -3,74 +3,143 @@
 Note: Having no "from __future__ import annotations" here is wanted (pydantic compatibility).
 """
 
-from typing import Any, Callable, Dict, List, Optional
+from typing import Annotated, Any, Callable, Dict, List, Optional
 
-try:
-    from pydantic import v1 as pydantic
-except ImportError:
-    import pydantic  # type: ignore
+import pydantic
+from pydantic.version import VERSION
 
 from arta.utils import ParsingErrorStrategy
 
+if not VERSION.startswith("1."):
+    # ----------------------------------
+    # For instantiation using rules_dict
+    class RuleRaw(pydantic.BaseModel):
+        """Pydantic model for validating a rule."""
 
-# ----------------------------------
-# For instantiation using rules_dict
-class RuleRaw(pydantic.BaseModel):
-    """Pydantic model for validating a rule."""
+        condition: Optional[Callable]
+        condition_parameters: Optional[Dict[str, Any]]
+        action: Callable
+        action_parameters: Optional[Dict[str, Any]]
 
-    condition: Optional[Callable]
-    condition_parameters: Optional[Dict[str, Any]]
-    action: Callable
-    action_parameters: Optional[Dict[str, Any]]
+        model_config = pydantic.ConfigDict(extra="forbid")
 
-    class Config:
-        extra = "forbid"
+    class RulesGroup(pydantic.RootModel):  # noqa
+        """Pydantic model for validating a rules group."""
 
+        root: Dict[str, RuleRaw]
 
-class RulesGroup(pydantic.BaseModel):
-    """Pydantic model for validating a rules group."""
+    class RulesDict(pydantic.RootModel):  # noqa
+        """Pydantic model for validating rules dict instanciation."""
 
-    __root__: Dict[str, RuleRaw]
+        root: Dict[str, RulesGroup]
 
+    # ----------------------------------
+    # For instantiation using config_path
+    class Condition(pydantic.BaseModel):
+        """Pydantic model for validating a condition."""
 
-class RulesDict(pydantic.BaseModel):
-    """Pydantic model for validating rules dict instanciation."""
+        description: str
+        validation_function: str
+        condition_parameters: Optional[Dict[str, Any]] = None
 
-    __root__: Dict[str, RulesGroup]
+    class RulesConfig(pydantic.BaseModel):
+        """Pydantic model for validating a rule group from config file."""
 
+        condition: Optional[str] = None
+        simple_condition: Optional[str] = None
+        action: Annotated[str, pydantic.StringConstraints(to_lower=True)]  # type: ignore
+        action_parameters: Optional[Any] = None
 
-# ----------------------------------
-# For instantiation using config_path
-class Condition(pydantic.BaseModel):
-    """Pydantic model for validating a condition."""
+        model_config = pydantic.ConfigDict(extra="allow")
 
-    description: str
-    validation_function: str
-    condition_parameters: Optional[Dict[str, Any]]
+    class Configuration(pydantic.BaseModel):
+        """Pydantic model for validating configuration files."""
 
+        conditions: Optional[Dict[str, Condition]] = None
+        conditions_source_modules: Optional[List[str]] = None
+        actions_source_modules: List[str]
+        custom_classes_source_modules: Optional[List[str]] = None
+        condition_factory_mapping: Optional[Dict[str, str]] = None
+        rules: Dict[str, Dict[str, Dict[str, RulesConfig]]]
+        parsing_error_strategy: Optional[ParsingErrorStrategy] = None
 
-class RulesConfig(pydantic.BaseModel):
-    """Pydantic model for validating a rule group from config file."""
+        model_config = pydantic.ConfigDict(extra="ignore")
 
-    condition: Optional[str]
-    simple_condition: Optional[str]
-    action: pydantic.constr(to_lower=True)  # type: ignore
-    action_parameters: Optional[Any]
+        @pydantic.field_validator("rules", mode="before")  # noqa
+        def upper_key(cls, vl):  # noqa
+            """Validate and uppercase keys for RulesConfig"""
+            for k, v in vl.items():
+                for kk, vv in v.items():
+                    for key, rules in [*vv.items()]:
+                        if key != str(key).upper():
+                            del vl[k][kk][key]
+                            vl[k][kk][str(key).upper()] = rules
+            return vl
 
-    class Config:
-        extra = "allow"
+else:
 
+    class BaseModelV2(pydantic.BaseModel):
+        """Wrapper to expose missed methods used elsewhere in the code"""
 
-class Configuration(pydantic.BaseModel):
-    """Pydantic model for validating configuration files."""
+        model_dump: Callable = pydantic.BaseModel.dict  # noqa
 
-    conditions: Optional[Dict[str, Condition]]
-    conditions_source_modules: Optional[List[str]]
-    actions_source_modules: List[str]
-    custom_classes_source_modules: Optional[List[str]]
-    condition_factory_mapping: Optional[Dict[str, str]]
-    rules: Dict[str, Dict[str, Dict[pydantic.constr(to_upper=True), RulesConfig]]]  # type: ignore
-    parsing_error_strategy: Optional[ParsingErrorStrategy]
+        @classmethod
+        def model_validate(cls, obj):  # noqa
+            return cls.parse_obj(obj)  # noqa
 
-    class Config:
-        extra = "ignore"
+    # ----------------------------------
+    # For instantiation using rules_dict
+    class RuleRaw(BaseModelV2):  # type: ignore[no-redef]
+        """Pydantic model for validating a rule."""
+
+        condition: Optional[Callable]
+        condition_parameters: Optional[Dict[str, Any]]
+        action: Callable
+        action_parameters: Optional[Dict[str, Any]]
+
+        class Config:
+            extra = "forbid"
+
+    class RulesGroup(pydantic.BaseModel):  # type: ignore[no-redef] # noqa
+        """Pydantic model for validating a rules group."""
+
+        __root__: Dict[str, RuleRaw]  # noqa
+
+    class RulesDict(BaseModelV2):  # type: ignore[no-redef]  # noqa
+        """Pydantic model for validating rules dict instanciation."""
+
+        __root__: Dict[str, RulesGroup]  # noqa
+
+    # ----------------------------------
+    # For instantiation using config_path
+    class Condition(BaseModelV2):  # type: ignore[no-redef]
+        """Pydantic model for validating a condition."""
+
+        description: str
+        validation_function: str
+        condition_parameters: Optional[Dict[str, Any]]
+
+    class RulesConfig(BaseModelV2):  # type: ignore[no-redef]
+        """Pydantic model for validating a rule group from config file."""
+
+        condition: Optional[str]
+        simple_condition: Optional[str]
+        action: pydantic.constr(to_lower=True)  # type: ignore
+        action_parameters: Optional[Any]
+
+        class Config:
+            extra = "allow"
+
+    class Configuration(BaseModelV2):  # type: ignore[no-redef]
+        """Pydantic model for validating configuration files."""
+
+        conditions: Optional[Dict[str, Condition]]
+        conditions_source_modules: Optional[List[str]]
+        actions_source_modules: List[str]
+        custom_classes_source_modules: Optional[List[str]]
+        condition_factory_mapping: Optional[Dict[str, str]]
+        rules: Dict[str, Dict[str, Dict[pydantic.constr(to_upper=True), RulesConfig]]]  # type: ignore
+        parsing_error_strategy: Optional[ParsingErrorStrategy]
+
+        class Config:
+            extra = "ignore"
diff --git a/tox.ini b/tox.ini
index 5f3ee84..e34568e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,17 +6,18 @@ env_list =
     py310
     py39
     pydantic1-{py39,py310,py311,py312}
-
 [testenv]
 description = run unit tests
 deps =
     pytest
+    pytest-cov
     pydantic>=2.0.0
-commands = pytest tests
+commands = pytest tests --cov --cov-append
 
-[testenv:pydantic1]
+[testenv:pydantic1-{py39,py310,py311,py312}]
 description = check backward compatibility with pydantic < 2.0.0
 deps =
     pytest
+    pytest-cov
     pydantic<2.0.0
-commands = pytest tests
+commands = pytest tests --cov --cov-append

problem_statement: Use Pydantic V2 models
**Is your feature request related to a problem? Please describe**

Use Pydantic V2 `BaseModel` class rather than V1 (maintenance purpose only).

**Describe the solution you'd like**

Migrate referring the Pydantic V2 [Migration Guide](https://docs.pydantic.dev/latest/migration/).

**Describe alternatives you've considered**

Use Pydantic V2/V1 backward compatibility:

```python
try:
    from pydantic import v1 as pydantic
except ImportError:
    import pydantic  # type: ignore
```
repo: MAIF/arta
test_cmd: pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
test_patch: diff --git a/tests/unit/test_engine_errors.py b/tests/unit/test_engine_errors.py
index d8ce10f..9893cd4 100644
--- a/tests/unit/test_engine_errors.py
+++ b/tests/unit/test_engine_errors.py
@@ -6,10 +6,7 @@ import pytest
 from arta import RulesEngine
 from arta.exceptions import ConditionExecutionError, RuleExecutionError
 
-try:
-    from pydantic import v1 as pydantic
-except ImportError:
-    import pydantic  # type: ignore
+import pydantic
 
 
 @pytest.mark.parametrize(