diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 54e9764a..0c2a3960 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,10 +13,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
-      - uses: abatilo/actions-poetry@v2
+      - uses: abatilo/actions-poetry@v3
         with:
           poetry-version: ${{ env.POETRY_VERSION }}
       - run: poetry install
@@ -46,15 +46,18 @@ jobs:
   pytest:
     name: pytest
     runs-on: ubuntu-latest
+    needs:
+      - linting
+      - version
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
-      - uses: abatilo/actions-poetry@v2
+      - uses: abatilo/actions-poetry@v3
         with:
           poetry-version: ${{ env.POETRY_VERSION }}
-      - uses: actions/setup-go@v4
+      - uses: actions/setup-go@v5
       - run: poetry install
       - run: go install github.com/richardlehane/siegfried/cmd/sf@latest
       - name: Unit test
diff --git a/acacore/__version__.py b/acacore/__version__.py
index f5f41e56..d539d50c 100644
--- a/acacore/__version__.py
+++ b/acacore/__version__.py
@@ -1 +1 @@
-__version__ = "3.1.0"
+__version__ = "3.1.1"
diff --git a/acacore/models/file.py b/acacore/models/file.py
index 80ac440e..0d070676 100644
--- a/acacore/models/file.py
+++ b/acacore/models/file.py
@@ -288,11 +288,13 @@ def get_action(
         action: Action | None = reduce(lambda acc, cur: acc or actions.get(cur), identifiers, None)
 
         if action and action.alternatives and (new_puid := action.alternatives.get(self.suffixes.lower(), None)):
-            puid: str = self.puid
+            puid: str | None = self.puid
             self.puid = new_puid
-            if new_action := self.get_action(actions, file_classes, set_match=set_match):
-                return new_action
-            self.puid = puid
+            if new_action := self.get_action(actions, file_classes):
+                action = new_action
+                self.signature = action.name
+            else:
+                self.puid = puid
 
         if set_match:
             self.action, self.action_data = (
diff --git a/acacore/models/reference_files.py b/acacore/models/reference_files.py
index 89ff5dfe..469edef1 100644
--- a/acacore/models/reference_files.py
+++ b/acacore/models/reference_files.py
@@ -47,13 +47,22 @@ class CustomSignature(BaseModel):
     :param extension: The file extension associated with the signature.
     """
 
+    puid: str
+    signature: str
     bof: str | None = None
     eof: str | None = None
     operator: str | None = None
-    puid: str | None = None
-    signature: str | None = None
     extension: str | None = None
 
+    # noinspection PyNestedDecorators
+    @model_validator(mode="after")
+    def _validate_model(self) -> Self:
+        if not self.bof and not self.eof:
+            raise ValueError("One of bof or eof must be set.")
+        if self.bof and self.eof and not self.operator:
+            raise ValueError("Operator must be set if both bof and eof are set.")
+        return self
+
 
 class IgnoreIfAction(NoDefaultsModel):
     """
diff --git a/pyproject.toml b/pyproject.toml
index b5a32b7d..7024d674 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "acacore"
-version = "3.1.0"
+version = "3.1.1"
 description = ""
 authors = ["Matteo Campinoti <matteo.campinoti94@gmail.com>"]
 license = "GPL-3.0"