diff --git a/build_all.sh b/build_all.sh
index 47884d6..50465b5 100755
--- a/build_all.sh
+++ b/build_all.sh
@@ -8,6 +8,9 @@
 # release_note.txt is copied to dist/ up front (with a warning if it has no
 # entry for the current version).
 #
+# By default, a step is skipped if its artifact already exists in dist/.
+# Pass --clean to remove existing dist/ artifacts and rebuild everything.
+#
 # All artifacts are collected (copied) under <repo>/dist/. Original outputs in
 # src/dist/, package/*/dist/, doc/manual/ are left in place. Wheel and AppImage
 # keep their original names (which already contain the version); manual,
@@ -15,17 +18,35 @@
 #
 # Re-uses scripts/build_env.sh and scripts/set_env.sh — the same pair invoked
 # by run.sh — so the venv at test/tmp/.venv stays the single source of Python
-# dependencies. `build` and `pyinstaller` are installed into that venv on
-# demand if not already there. Flatpak and AppImage build in their own
-# container/sandbox; their build.sh scripts have their own toolchain checks.
+# dependencies. `build`, `pyinstaller`, `sphinx` and `linuxdoc` are installed
+# into that venv on demand if not already there. Flatpak and AppImage build in
+# their own container/sandbox; their build.sh scripts have their own toolchain
+# checks.
 
 set -e
 
+CLEAN=0
+for arg in "$@"; do
+    case "$arg" in
+        --clean|-c) CLEAN=1 ;;
+        *) echo "Unknown option: $arg" >&2; exit 1 ;;
+    esac
+done
+
 SCRIPT_DIR=$(realpath "$(dirname "$0")")
 VERSION=$(cat "$SCRIPT_DIR/src/VERSION")
 DIST_DIR="$SCRIPT_DIR/dist"
 mkdir -p "$DIST_DIR"
 
+if [ "$CLEAN" -eq 1 ]; then
+    echo "-- clean: removing existing dist artifacts for version $VERSION"
+    rm -f "$DIST_DIR/testium-manual-${VERSION}.pdf"
+    rm -f "$DIST_DIR"/testium-${VERSION}-*.whl
+    rm -f "$DIST_DIR/testium-${VERSION}"
+    rm -f "$DIST_DIR/testium-${VERSION}.flatpak"
+    rm -f "$DIST_DIR"/Testium-${VERSION}-*.AppImage
+fi
+
 # Release note: copy it to dist/ and warn (but don't fail) if it has no entry
 # for the current version.
 RELEASE_NOTE_SRC="$SCRIPT_DIR/release_note.txt"
@@ -42,9 +63,6 @@ export REQ_PATH="$SCRIPT_DIR/src/requirements.txt"
 bash "$SCRIPT_DIR/scripts/build_env.sh"
 source "$SCRIPT_DIR/scripts/set_env.sh"
 
-# Ensure wheel/PyInstaller toolchains are present in the venv.
-python -m pip install --quiet --upgrade build pyinstaller
-
 step() {
     echo
     echo "================================================================"
@@ -52,51 +70,90 @@ step() {
     echo "================================================================"
 }
 
+skip() { echo "  (already built — skipping)"; }
+
 # 1. Manual PDF
-step "1/5  Manual PDF (version $VERSION)"
-bash "$SCRIPT_DIR/doc/manual/sphinx/build_doc.sh"
-MANUAL_SRC="$SCRIPT_DIR/doc/manual/testium_manual.pdf"
 MANUAL="$DIST_DIR/testium-manual-${VERSION}.pdf"
-cp -f "$MANUAL_SRC" "$MANUAL"
+step "1/5  Manual PDF (version $VERSION)"
+if [ ! -f "$MANUAL" ]; then
+    python -m pip install --quiet --upgrade sphinx linuxdoc
+    bash "$SCRIPT_DIR/doc/manual/sphinx/build_doc.sh"
+    cp -f "$SCRIPT_DIR/doc/manual/testium_manual.pdf" "$MANUAL"
+else
+    skip
+fi
 
 # 2. Wheel — PEP 427 name kept (already contains version)
 step "2/5  Wheel (version $VERSION)"
-(
-    cd "$SCRIPT_DIR/src"
-    rm -rf dist build *.egg-info
-    python -m build --wheel
-)
-WHEEL_SRC=$(ls -1t "$SCRIPT_DIR/src/dist"/*.whl | head -1)
-WHEEL="$DIST_DIR/$(basename "$WHEEL_SRC")"
-cp -f "$WHEEL_SRC" "$WHEEL"
+WHEEL=$(ls -1t "$DIST_DIR"/testium-${VERSION}-*.whl 2>/dev/null | head -1)
+if [ -z "$WHEEL" ]; then
+    python -m pip install --quiet --upgrade build
+    (
+        cd "$SCRIPT_DIR/src"
+        rm -rf dist build *.egg-info
+        python -m build --wheel
+    )
+    WHEEL_SRC=$(ls -1t "$SCRIPT_DIR/src/dist"/*.whl | head -1)
+    WHEEL="$DIST_DIR/$(basename "$WHEEL_SRC")"
+    cp -f "$WHEEL_SRC" "$WHEEL"
+else
+    skip
+fi
 
 # 3. PyInstaller binary
-step "3/5  PyInstaller binary (version $VERSION)"
-bash "$SCRIPT_DIR/package/pyinstaller/build.sh"
-PYI_SRC="$SCRIPT_DIR/package/pyinstaller/dist/testium"
 PYI_BIN="$DIST_DIR/testium-${VERSION}"
-cp -f "$PYI_SRC" "$PYI_BIN"
+step "3/5  PyInstaller binary (version $VERSION)"
+if [ ! -f "$PYI_BIN" ]; then
+    python -m pip install --quiet --upgrade pyinstaller
+    bash "$SCRIPT_DIR/package/pyinstaller/build.sh"
+    cp -f "$SCRIPT_DIR/package/pyinstaller/dist/testium" "$PYI_BIN"
+else
+    skip
+fi
 
 # 4. Flatpak bundle
-step "4/5  Flatpak bundle (version $VERSION)"
-(
-    cd "$SCRIPT_DIR/package/flatpak"
-    bash build.sh
-)
-FLATPAK_SRC="$SCRIPT_DIR/package/flatpak/testium.flatpak"
 FLATPAK_BUNDLE="$DIST_DIR/testium-${VERSION}.flatpak"
-cp -f "$FLATPAK_SRC" "$FLATPAK_BUNDLE"
+step "4/5  Flatpak bundle (version $VERSION)"
+if [ ! -f "$FLATPAK_BUNDLE" ]; then
+    FLATPAK_DEPS=(
+        "org.kde.Platform//6.10"
+        "org.kde.Sdk//6.10"
+        "io.qt.PySide.BaseApp//6.10"
+    )
+    if ! flatpak remotes --user | grep -q "^flathub"; then
+        echo "  Adding Flathub remote"
+        flatpak remote-add --user --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
+    fi
+    for dep in "${FLATPAK_DEPS[@]}"; do
+        if ! flatpak info --user "$dep" &>/dev/null && ! flatpak info --system "$dep" &>/dev/null; then
+            echo "  Installing Flatpak dependency: $dep"
+            flatpak install --user --noninteractive flathub "$dep"
+        fi
+    done
+    (
+        cd "$SCRIPT_DIR/package/flatpak"
+        bash build.sh
+    )
+    cp -f "$SCRIPT_DIR/package/flatpak/testium.flatpak" "$FLATPAK_BUNDLE"
+else
+    skip
+fi
 
 # 5. AppImage
 step "5/5  AppImage (version $VERSION)"
-(
-    cd "$SCRIPT_DIR/package/appimage"
-    bash build.sh
-)
-APPIMAGE_SRC=$(ls -1t "$SCRIPT_DIR/package/appimage"/*.AppImage 2>/dev/null | head -1)
-APPIMAGE="$DIST_DIR/$(basename "$APPIMAGE_SRC")"
-cp -f "$APPIMAGE_SRC" "$APPIMAGE"
-chmod +x "$APPIMAGE"
+APPIMAGE=$(ls -1t "$DIST_DIR"/Testium-${VERSION}-*.AppImage 2>/dev/null | head -1)
+if [ -z "$APPIMAGE" ]; then
+    (
+        cd "$SCRIPT_DIR/package/appimage"
+        bash build.sh
+    )
+    APPIMAGE_SRC=$(ls -1t "$SCRIPT_DIR/package/appimage"/*.AppImage 2>/dev/null | head -1)
+    APPIMAGE="$DIST_DIR/$(basename "$APPIMAGE_SRC")"
+    cp -f "$APPIMAGE_SRC" "$APPIMAGE"
+    chmod +x "$APPIMAGE"
+else
+    skip
+fi
 
 step "All packages built"
 printf "  manual       : %s\n" "$MANUAL"
diff --git a/doc/manual/testium_manual.pdf b/doc/manual/testium_manual.pdf
index e1a2fcd..c03d73c 100644
Binary files a/doc/manual/testium_manual.pdf and b/doc/manual/testium_manual.pdf differ
diff --git a/src/VERSION b/src/VERSION
index 8294c18..b1e80bb 100644
--- a/src/VERSION
+++ b/src/VERSION
@@ -1 +1 @@
-0.1.2
\ No newline at end of file
+0.1.3