diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 782402d56c..adf0acb18c 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -35,6 +35,14 @@ jobs:
           path: website
           fetch-depth: 0 # full history required to determine last edit
 
+      - name: Fetch full history for submodules
+        working-directory: website
+        run: git submodule foreach --recursive "git fetch --unshallow --all 2>/dev/null || git fetch --all"
+
+      - name: Inject last_modified_at dates from submodules
+        working-directory: website
+        run: bash inject_dates.sh
+
       - name: Fetch - precice develop
         uses: actions/checkout@v4
         with:
@@ -72,6 +80,19 @@ jobs:
           bundler-cache: true
           working-directory: website
 
+      - name: Patch jekyll-last-modified-at to respect frontmatter
+        working-directory: website
+        run: |
+            set -euo pipefail
+            shopt -s nullglob
+            hook_files=(vendor/bundle/ruby/*/gems/jekyll-last-modified-at-*/lib/jekyll-last-modified-at/hook.rb)
+            if [ "${#hook_files[@]}" -ne 1 ]; then
+              echo "Expected exactly one jekyll-last-modified-at hook.rb file, found ${#hook_files[@]}:" >&2
+              printf '  %s\n' "${hook_files[@]}" >&2
+              exit 1
+            fi
+            sed -i 's/item\.data\["last_modified_at"\] = Determinator/item.data["last_modified_at"] ||= Determinator/' "${hook_files[0]}"
+
       - name: Build website
         working-directory: website
         env:
diff --git a/inject_dates.sh b/inject_dates.sh
new file mode 100644
index 0000000000..6de8156b1b
--- /dev/null
+++ b/inject_dates.sh
@@ -0,0 +1,53 @@
+#!/bin/bash
+# inject_dates.sh
+# Run this from the website root before jekyll build.
+# It goes into each submodule, finds every markdown file,
+# gets its true last-commit date from git, and injects/updates
+# the last_modified_at field in the frontmatter so that
+# jekyll-last-modified-at uses the correct date instead of
+# falling back to filesystem mtime.
+
+set -euo pipefail
+
+git submodule foreach --recursive '
+  echo "==> Processing submodule: $displaypath"
+
+  git ls-files "*.md" "*.markdown" | while IFS= read -r file; do
+
+    last_date=$(git log -1 --date=format:"%Y-%m-%d %H:%M:%S" --pretty=format:"%cd" -- "$file" 2>/dev/null)
+
+    if [ -z "$last_date" ]; then
+      echo "    SKIP (no git date): $file"
+      continue
+    fi
+
+    filepath="$toplevel/$displaypath/$file"
+
+    if [ ! -f "$filepath" ]; then
+      echo "    SKIP (not on disk): $file"
+      continue
+    fi
+
+    if awk '\''NR==1 { if ($0 == "---") { in_front=1; next } else { exit 1 } } in_front && NR>1 && $0 == "---" { exit 0 } END { exit 1 }'\'' "$filepath"; then
+
+      if grep -q "^last_modified_at:" "$filepath"; then
+        sed -i "s|^last_modified_at:.*|last_modified_at: $last_date|" "$filepath"
+      else
+        sed -i "0,/^---/{s|^---|---\nlast_modified_at: $last_date|}" "$filepath"
+      fi
+
+    else
+      tmpfile=$(mktemp)
+      printf -- "---\nlast_modified_at: %s\n---\n" "$last_date" | cat - "$filepath" > "$tmpfile"
+      mv "$tmpfile" "$filepath"
+    fi
+
+    echo "    OK: $file -> $last_date"
+
+  done
+
+  echo "    done."
+'
+
+echo ""
+echo "All submodule dates injected successfully."
\ No newline at end of file