diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 6137864..ca693de 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -31,6 +31,7 @@ jobs:
           path: eggs
           key: ${{ runner.OS }}-build-python${{ matrix.python }}-${{ matrix.plone }}
       - name: Set up Python ${{ matrix.python }}
+        # don't upgrade this action version, as we want to support plone52/py38
         uses: actions/setup-python@v3
         with:
           python-version: ${{ matrix.python }}
diff --git a/.github/workflows/zpretty.yml b/.github/workflows/zpretty.yml
index 180f0e9..154b42a 100644
--- a/.github/workflows/zpretty.yml
+++ b/.github/workflows/zpretty.yml
@@ -6,20 +6,20 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.8]
+        python-version: [3.11]
 
     steps:
       # git checkout
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       # python setup
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
 
       # python cache
-      - uses: actions/cache@v1
+      - uses: actions/cache@v4
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
diff --git a/CHANGES.rst b/CHANGES.rst
index 4134f11..e217598 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,6 +4,9 @@ Changelog
 5.6.4 (unreleased)
 ------------------
 
+- fix file:/// as external link in summary
+  [mamico]
+
 - Update it translations
   [lucabel]
 
diff --git a/src/redturtle/volto/restapi/serializer/summary.py b/src/redturtle/volto/restapi/serializer/summary.py
index f1b49bb..5cc8222 100644
--- a/src/redturtle/volto/restapi/serializer/summary.py
+++ b/src/redturtle/volto/restapi/serializer/summary.py
@@ -81,9 +81,15 @@ def get_remote_url(self):
             value = self.context.getRemoteUrl
         if not value:
             return ""
-        if value.startswith("http"):
-            # it isn't an internal link, so we can return it
+
+        # it isn't an internal link, so we can return it
+        if value.startswith("http:"):
+            return value
+        if value.startswith("https:"):
             return value
+        if value.startswith("file:"):
+            return value
+
         path = replace_link_variables_by_paths(context=self.context, url=value)
 
         url = uid_to_url(path)