diff --git a/gfd/__init__.py b/gfd/__init__.py
index 0e0b578..adc7c6c 100644
--- a/gfd/__init__.py
+++ b/gfd/__init__.py
@@ -1,108 +1 @@
-from PySide6 import QtWidgets, QtCore
-import gfd.i18n as i18n
-from gfd import sfd
-
-
-class GFDWidget(QtWidgets.QWidget):
-    def __init__(self, tr):
-        super().__init__()
-        self.tr = tr
-        self.setWindowTitle(self.tr("window_title"))
-        self.resize(400, 220)
-
-        self.label = QtWidgets.QLabel(
-            self.tr("hello_world"),
-            alignment=QtCore.Qt.AlignmentFlag.AlignCenter,
-        )
-
-        self.combo = QtWidgets.QComboBox()
-        self.combo.addItem(self.tr("loading_installers") + "…")
-
-        self.refresh_btn = QtWidgets.QPushButton("⟳ " + self.tr("refresh"))
-        self.refresh_btn.clicked.connect(self.reload_installers)
-
-        combo_layout = QtWidgets.QHBoxLayout()
-        combo_layout.addWidget(self.combo)
-        combo_layout.addWidget(self.refresh_btn)
-
-        self.md5_label = QtWidgets.QLabel(
-            "", alignment=QtCore.Qt.AlignmentFlag.AlignCenter
-        )
-
-        layout = QtWidgets.QVBoxLayout(self)
-        layout.addWidget(self.label)
-        layout.addLayout(combo_layout)
-        layout.addWidget(self.md5_label)
-
-        self.combo.currentIndexChanged.connect(self.on_selection_changed)
-
-        QtCore.QTimer.singleShot(0, self.load_installers_async)
-
-    def reload_installers(self):
-        """Triggered by the refresh button."""
-        self.refresh_btn.setEnabled(False)
-        self.combo.clear()
-        self.combo.addItem(self.tr("loading_installers") + "…")
-        self.load_installers_async()
-
-    def load_installers_async(self):
-        """Fetch installer options without freezing the UI."""
-        self.thread = QtCore.QThread()
-        self.worker = SFDWorker()
-        self.worker.moveToThread(self.thread)
-
-        self.thread.started.connect(self.worker.run)
-        self.worker.finished.connect(self.thread.quit)
-        self.worker.finished.connect(self.worker.deleteLater)
-        self.thread.finished.connect(self.thread.deleteLater)
-        self.worker.result_ready.connect(self.populate_installers)
-
-        self.thread.start()
-
-    @QtCore.Slot(list)
-    def populate_installers(self, installers):
-        self.refresh_btn.setEnabled(True)
-        self.combo.clear()
-
-        if not installers:
-            self.combo.addItem(self.tr("no_installers_found"))
-            self.md5_label.setText("")
-            return
-
-        self.installers = installers
-        for item in installers:
-            self.combo.addItem(item["name"], item["md5"])
-
-        self.combo.setCurrentIndex(0)
-        self.on_selection_changed(0)
-
-    @QtCore.Slot(int)
-    def on_selection_changed(self, index):
-        if not hasattr(self, "installers") or not self.installers:
-            return
-        md5 = self.combo.currentData()
-        name = self.combo.currentText()
-        self.md5_label.setText(f"<b>{name}</b><br>MD5: <code>{md5 or 'N/A'}</code>")
-
-
-class SFDWorker(QtCore.QObject):
-    """Background worker to fetch installers safely."""
-
-    finished = QtCore.Signal()
-    result_ready = QtCore.Signal(list)
-
-    @QtCore.Slot()
-    def run(self):
-        data = sfd.fetchInstallerOptions()
-        self.result_ready.emit(data)
-        self.finished.emit()
-
-
-def run(lang="es"):
-    import sys
-
-    app = QtWidgets.QApplication(sys.argv)
-    tr = i18n.Translator(lang)
-    w = GFDWidget(tr)
-    w.show()
-    sys.exit(app.exec())
+from .app import run
diff --git a/gfd/app.py b/gfd/app.py
new file mode 100644
index 0000000..2c962b1
--- /dev/null
+++ b/gfd/app.py
@@ -0,0 +1,13 @@
+from PySide6 import QtWidgets
+from gfd.ui.main_window import GFDWidget
+from gfd.i18n import Translator
+
+
+def run(lang="es"):
+    import sys
+
+    app = QtWidgets.QApplication(sys.argv)
+    tr = Translator(lang)
+    window = GFDWidget(tr)
+    window.show()
+    sys.exit(app.exec())
diff --git a/gfd/core/installers.py b/gfd/core/installers.py
new file mode 100644
index 0000000..2fc7d07
--- /dev/null
+++ b/gfd/core/installers.py
@@ -0,0 +1,98 @@
+import time
+import re
+import unicodedata
+from gfd.core import sfd
+
+SUPPORTED_INSTALLERS = [
+    {
+        "os_type": "ubuntu24",
+        "name": "Usuarios Linux - Ubuntu 24.04 LTS (DEB 64bits) - 78 MB",
+        "md5": "bdc871e15f2096f930b285f0ed799aa0",
+    },
+    {
+        "os_type": "debian",
+        "name": "Usuarios Linux - Ubuntu 24.04 LTS (DEB 64bits) - 78 MB",
+        "md5": "bdc871e15f2096f930b285f0ed799aa0",
+    },
+]
+
+
+def _normalize(t):
+    return re.sub(r"\s+", " ", unicodedata.normalize("NFKD", t).lower()).strip()
+
+
+def _fetch(max_attempts=3, delay=2):
+    for i in range(max_attempts):
+        data = sfd.fetchInstallerOptions()
+
+        if data:
+            return data
+
+        if i < max_attempts - 1:
+            time.sleep(delay)
+
+    return []
+
+
+def get_available_installers(os_type, installers=None):
+    """
+    Return a list of confirmed available installers for the given OS type.
+
+    If an installer is listed, it means that for a given OS type:
+        - There is a supported installation routine.
+        - There is a downloadable archive from Soporte Firma Digital.
+    """
+    src = installers or SUPPORTED_INSTALLERS
+    locals_ = [i for i in src if i["os_type"] == os_type]
+
+    if not locals_:
+        return []
+
+    remote = _fetch()
+
+    if not remote:
+        return []
+
+    rmap = {_normalize(r["name"]): r.get("md5") for r in remote}
+    confirmed = []
+
+    for local in locals_:
+        lname, lmd5 = (
+            _normalize(local["name"]),
+            (local.get("md5") or "").lower() or None,
+        )
+        rmd5 = rmap.get(lname)
+
+        if (lmd5 == rmd5) or (lmd5 is None and rmd5 is None):
+            confirmed.append((local["name"], lmd5))
+
+    return confirmed
+
+
+# TODO: Routine to check for installed version
+def get_installed_version():
+    """
+    Return the current installed version data, or empty if not installed.
+    """
+    return []  # Return always empty for now
+
+
+if __name__ == "__main__":
+    os_type = "debian"
+    print(f"=== TEST: {os_type.upper()} Installer Validation ===")
+    confirmed = get_available_installers(os_type)
+    print(
+        f"{len(confirmed)} confirmed installer(s):"
+        if confirmed
+        else "No confirmed installers found."
+    )
+
+    for n, m in confirmed:
+        print(f" - {n} (MD5={m or 'N/A'})")
+
+    installed = get_installed_version()
+
+    if not installed:
+        print("Status: NOT INSTALLED")
+    else:
+        print(f"Installed: {installed[0]} MD5={installed[1]}")
diff --git a/gfd/core/osinfo.py b/gfd/core/osinfo.py
new file mode 100644
index 0000000..2025b3b
--- /dev/null
+++ b/gfd/core/osinfo.py
@@ -0,0 +1,74 @@
+import platform
+import re
+from pathlib import Path
+
+
+def _read_os_release():
+    """Read and parse /etc/os-release or /usr/lib/os-release if available."""
+    paths = [Path("/etc/os-release"), Path("/usr/lib/os-release")]
+    data = {}
+
+    for path in paths:
+        if path.exists():
+            try:
+                for line in path.read_text(encoding="utf-8").splitlines():
+                    if "=" in line:
+                        key, val = line.split("=", 1)
+                        data[key.strip()] = val.strip().strip('"')
+                break
+            except Exception:
+                pass
+    return data
+
+
+def get_os_type():
+    """
+    Detect and return a simple OS type string.
+
+    Returns one of:
+      'macos', 'windows', 'ubuntu24', 'ubuntu22', 'ubuntu20',
+      'debian', 'arch', 'rpm', or None if unsupported.
+    """
+    system = platform.system().lower()
+    os_type = None
+
+    if system == "darwin":
+        os_type = "macos"
+
+    elif system == "windows":
+        os_type = "windows"
+
+    elif system == "linux":
+        info = _read_os_release()
+        id_name = info.get("ID", "").lower()
+        version_id = info.get("VERSION_ID", "")
+
+        # Ubuntu
+        if id_name == "ubuntu":
+            if version_id.startswith("24"):
+                os_type = "ubuntu24"
+            elif version_id.startswith("22"):
+                os_type = "ubuntu22"
+            elif version_id.startswith("20"):
+                os_type = "ubuntu20"
+
+        # Debian (11 or newer supported)
+        elif id_name == "debian":
+            try:
+                version_num = int(re.findall(r"\d+", version_id or "0")[0])
+            except IndexError:
+                version_num = 0
+            if version_num >= 11:
+                os_type = "debian"
+
+        # Arch / RPM-based
+        elif "arch" in id_name:
+            os_type = "arch"
+        elif id_name in ["fedora", "rhel", "centos", "rocky", "alma", "opensuse"]:
+            os_type = "rpm"
+
+    return os_type
+
+
+if __name__ == "__main__":
+    print("Detected OS type:", get_os_type() or "NOT SUPPORTED")
diff --git a/gfd/core/routines.py b/gfd/core/routines.py
new file mode 100644
index 0000000..21a9342
--- /dev/null
+++ b/gfd/core/routines.py
@@ -0,0 +1,52 @@
+"""
+routines.py - OS-specific installer routines
+
+Defines a registry of install routines by OS type.
+If the current OS is supported and has an associated installer,
+the matching routine can be executed to perform installation steps.
+"""
+
+from gfd.core.osinfo import get_os_type
+
+
+def install_ubuntu24():
+    """Simulated install routine for Ubuntu 24.04."""
+    print("Running Ubuntu 24.04 (DEB) installation routine...")
+
+
+def install_debian():
+    """Simulated install routine for Debian."""
+    print("Running Debian installation routine (using Ubuntu 24 package)...")
+
+
+SUPPORTED_ROUTINES = {
+    "ubuntu24": install_ubuntu24,
+    "debian": install_debian,
+}
+
+
+def run_install_routine(os_type=None):
+    """
+    Run the appropriate install routine for the given OS type.
+
+    Args:
+        os_type (str | None): OS key (e.g. 'ubuntu24', 'macos').
+            If None, automatically detects current OS.
+
+    Returns:
+        bool: True if the OS is supported and a routine was executed, else False.
+    """
+    os_type = os_type or get_os_type()
+    if not os_type:
+        return False
+
+    routine = SUPPORTED_ROUTINES.get(os_type)
+    if not routine:
+        return False
+
+    routine()
+    return True
+
+
+if __name__ == "__main__":
+    run_install_routine()
diff --git a/gfd/core/sfd.py b/gfd/core/sfd.py
new file mode 100644
index 0000000..5f6aa36
--- /dev/null
+++ b/gfd/core/sfd.py
@@ -0,0 +1,116 @@
+"""
+sfd.py - Installer List Parser for Soporte Firma Digital
+
+This module is responsible for fetching and parsing the list of available
+digital signature installers from the official Soporte Firma Digital website.
+
+It retrieves both the visible installer names (from the page’s <select> element)
+and the associated MD5 hashes (embedded within inline JavaScript).
+
+The parsed results are used by the UI layer to display which installers
+are available and to match system OS types to the appropriate installer.
+"""
+
+import re
+import unicodedata
+import requests
+from bs4 import BeautifulSoup
+
+SFD_URL = "https://soportefirmadigital.com/sfdj/dl.aspx"
+
+
+def _normalize_text(text: str) -> str:
+    """
+    Normalize text for consistent matching.
+
+    Steps:
+        1. Remove accents and diacritics using Unicode normalization.
+        2. Replace consecutive spaces with a single space.
+        3. Convert to lowercase and strip leading/trailing whitespace.
+
+    Args:
+        text (str): Raw string to normalize.
+
+    Returns:
+        str: Cleaned, normalized string suitable for fuzzy matching.
+    """
+    text = unicodedata.normalize("NFKD", text)
+    text = "".join(c for c in text if not unicodedata.combining(c))
+    return re.sub(r"\s+", " ", text).strip().lower()
+
+
+def fetchInstallerOptions(url: str = SFD_URL):
+    """
+    Fetch and parse the installer list from the Soporte Firma Digital website.
+
+    Example output:
+        [
+            {"name": "Usuarios Linux - Ubuntu 24.04 LTS (DEB 64bits) - 78 MB",
+             "md5": "bdc871e15f2096f930b285f0ed799aa0"},
+            {"name": "Usuarios Windows JCOP3 - 189 MB",
+             "md5": "596c347e409d00388c3c1ee0a72b96c0"},
+            ...
+        ]
+
+    Args:
+        url (str, optional): Target URL to fetch. Defaults to SFD_URL.
+
+    Returns:
+        list[dict]: Each dict contains:
+            - "name" (str): Installer display name.
+            - "md5" (str | None): MD5 checksum (if found), else None.
+    """
+    try:
+        r = requests.get(url, timeout=8)
+        r.raise_for_status()
+    except requests.RequestException:
+        # Network error, timeout, or unreachable server
+        return []
+
+    soup = BeautifulSoup(r.text, "html.parser")
+
+    # Extract installer names from the dropdown list
+    installers = [
+        opt.text.strip()
+        for opt in soup.select("#ctl00_certContents_ddlInstaladores option")
+    ]
+    if not installers:
+        return []
+
+    # Parse embedded JavaScript to extract name, MD5 mapping
+    md5s = {}
+    for name, md5 in re.findall(
+        r"text\s*==\s*'([^']+)'.*?MD5\s*[:=]\s*([A-Za-z0-9]+)",
+        r.text,
+        re.DOTALL,
+    ):
+        md5 = md5.lower()
+        if re.fullmatch(r"[0-9a-f]{32}", md5):  # Only valid 32-character MD5
+            md5s[_normalize_text(name)] = md5
+
+    # Merge name list with MD5 map
+    results = []
+    for inst in installers:
+        n = _normalize_text(inst)
+        md5 = md5s.get(n)
+
+        # Try fuzzy match if exact normalization key not found
+        if not md5:
+            for key, val in md5s.items():
+                if key in n or n in key:
+                    md5 = val
+                    break
+
+        results.append({"name": inst, "md5": md5})
+
+    return results
+
+
+if __name__ == "__main__":
+    """
+    Fetch and print all installers to stdout.
+    """
+    installers = fetchInstallerOptions()
+    print(f"Fetched {len(installers)} installers from {SFD_URL}\n")
+    for item in installers:
+        print(f"{item['name']:<70}  MD5={item['md5'] or 'N/A'}")
diff --git a/gfd/i18n/en.py b/gfd/i18n/en.py
index 9ae74e5..52163f8 100644
--- a/gfd/i18n/en.py
+++ b/gfd/i18n/en.py
@@ -1,7 +1,11 @@
 translations = {
-    "hello_world": "Hello, World!",
     "window_title": "Digital Signature Manager",
-    "no_installers_found": "Could not update installer list",
-    "loading_installers": "Loading Installers",
-    "refresh": "Refresh",
+    "no_install_message": "Digital signature not installed",
+    "recommended_version": "Recommended version:",
+    "install": "Install",
+    "installed_version": "Installed version:",
+    "latest_version_installed": "Latest version installed",
+    "update_digital_signature": "Update Digital Signature",
+    "no_installers_found": "Could not fetch the installer list",
+    "loading_installers": "Loading installers",
 }
diff --git a/gfd/i18n/es.py b/gfd/i18n/es.py
index 20d5330..da12d98 100644
--- a/gfd/i18n/es.py
+++ b/gfd/i18n/es.py
@@ -1,7 +1,11 @@
 translations = {
-    "hello_world": "¡Hola, Mundo!",
     "window_title": "Gestor de Firma Digital",
-    "no_installers_found": "No se pudo actualizar la lista de instaladores",
+    "no_install_message": "No tiene la firma digital instalada",
+    "recommended_version": "Versión recomendada:",
+    "install": "Instalar",
+    "installed_version": "Versión instalada:",
+    "latest_version_installed": "Última versión instalada",
+    "update_digital_signature": "Actualizar Firma Digital",
+    "no_installers_found": "No se pudo obtener la lista de instaladores",  # ES
     "loading_installers": "Cargando instaladores",
-    "refresh": "Buscar",
 }
diff --git a/gfd/sfd.py b/gfd/sfd.py
deleted file mode 100644
index c082ccb..0000000
--- a/gfd/sfd.py
+++ /dev/null
@@ -1,68 +0,0 @@
-import re
-import unicodedata
-import requests
-from bs4 import BeautifulSoup
-
-SFD_URL = "https://soportefirmadigital.com/sfdj/dl.aspx"
-
-
-def _normalize_text(text: str) -> str:
-    """Internal: remove accents, extra spaces, and lowercase."""
-    text = unicodedata.normalize("NFKD", text)
-    text = "".join(c for c in text if not unicodedata.combining(c))
-    return re.sub(r"\s+", " ", text).strip().lower()
-
-
-def fetchInstallerOptions(url: str = SFD_URL):
-    """
-    Fetch the list of installer options from the given Soporte Firma Digital page.
-
-    Args:
-        url (str, optional): Page URL to fetch. Defaults to SFD_URL.
-
-    Returns:
-        list[dict]: Each item is {'name': <str>, 'md5': <str or None>}
-    """
-    try:
-        r = requests.get(url, timeout=8)
-        r.raise_for_status()
-    except requests.RequestException:
-        return []
-
-    soup = BeautifulSoup(r.text, "html.parser")
-
-    installers = [
-        opt.text.strip()
-        for opt in soup.select("#ctl00_certContents_ddlInstaladores option")
-    ]
-    if not installers:
-        return []
-
-    # Extract valid MD5 hashes from embedded JavaScript
-    md5s = {}
-    for name, md5 in re.findall(
-        r"text\s*==\s*'([^']+)'.*?MD5\s*[:=]\s*([A-Za-z0-9]+)",
-        r.text,
-        re.DOTALL,
-    ):
-        md5 = md5.lower()
-        if re.fullmatch(r"[0-9a-f]{32}", md5):  # only valid 32-char hex hashes
-            md5s[_normalize_text(name)] = md5
-
-    results = []
-    for inst in installers:
-        n = _normalize_text(inst)
-        md5 = md5s.get(n)
-        if not md5:
-            for key, val in md5s.items():
-                if key in n or n in key:
-                    md5 = val
-                    break
-        results.append({"name": inst, "md5": md5})
-
-    return results
-
-
-if __name__ == "__main__":
-    for item in fetchInstallerOptions():
-        print(f"{item['name']:<70}  MD5={item['md5'] or 'N/A'}")
diff --git a/gfd/ui/main_window.py b/gfd/ui/main_window.py
new file mode 100644
index 0000000..a201260
--- /dev/null
+++ b/gfd/ui/main_window.py
@@ -0,0 +1,222 @@
+from PySide6 import QtWidgets, QtCore
+from gfd.core.osinfo import get_os_type
+from gfd.core.installers import get_available_installers, get_installed_version
+
+
+def check_installation_status():
+    """
+    Determine system support and installer availability.
+
+    Returns:
+        (installed: [version, md5] or [],
+         available: list[[version, md5]],
+         recommended: [version, md5] or None)
+    """
+    os_type = get_os_type()
+
+    if not os_type:
+        return [], [], None
+
+    available = get_available_installers(os_type)
+    installed = get_installed_version()
+
+    if not available:
+        return installed, [], None
+
+    # Assume the first installer in the list is the recommended one
+    recommended = available[0]
+
+    return installed, available, recommended
+
+
+class GFDWidget(QtWidgets.QWidget):
+    def __init__(self, tr):
+        super().__init__()
+        self.tr = tr
+        self.setWindowTitle(self.tr("window_title"))
+        self.resize(600, 400)
+
+        self.main_layout = QtWidgets.QVBoxLayout(self)
+        self.main_layout.setContentsMargins(20, 20, 20, 20)
+
+        # Card container
+        self.card = QtWidgets.QFrame()
+        self.card_layout = QtWidgets.QVBoxLayout(self.card)
+        self.card_layout.setSpacing(12)
+
+        # Title
+        self.title = QtWidgets.QLabel(self.tr("window_title"))
+        self.title.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
+        self.title.setStyleSheet("font-weight: bold; font-size: 16px;")
+        self.card_layout.addWidget(self.title)
+
+        # Content area
+        self.content_area = QtWidgets.QWidget()
+        self.content_layout = QtWidgets.QVBoxLayout(self.content_area)
+        self.content_layout.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
+        self.card_layout.addWidget(self.content_area)
+
+        # Footer
+        self.footer = QtWidgets.QHBoxLayout()
+        self.footer.addStretch()
+        self.refresh_btn = QtWidgets.QPushButton("⟳")
+        self.refresh_btn.setFixedWidth(36)
+        self.refresh_btn.clicked.connect(self.refresh_state)
+        self.footer.addWidget(self.refresh_btn)
+        self.card_layout.addLayout(self.footer)
+
+        self.main_layout.addWidget(self.card)
+        self.setStyleSheet("""
+            QPushButton {
+                border-radius: 8px;
+                padding: 6px 12px;
+                font-weight: bold;
+            }
+            QPushButton[primary="true"] {
+                background-color: #2f80ed;
+                color: white;
+            }
+            QPushButton[primary="true"]:disabled {
+                background-color: #a0c4ff;
+            }
+            QLabel, QComboBox {
+                font-size: 16px;
+            }
+        """)
+
+        self.states = ["not_installed", "installed", "update_available"]
+        self.current_state = 0
+
+        # Run initial refresh
+        self.refresh_state()
+
+    # --- LOGIC ---
+
+    def refresh_state(self):
+        """Fetch installer list and determine status."""
+        self.refresh_btn.setEnabled(False)
+        self.clear_content()
+        loading_label = QtWidgets.QLabel(self.tr("loading_installers") + "…")
+        loading_label.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
+        self.content_layout.addWidget(loading_label)
+
+        QtCore.QTimer.singleShot(150, self._refresh_check)
+
+    def _refresh_check(self):
+        """Evaluate OS type, installed version, and available installers."""
+        self.installed, self.available, self.recommended = check_installation_status()
+
+        print("\n=== INSTALLER STATUS DEBUG ===")
+        if not self.available:
+            print("No available installers for this OS.")
+        else:
+            for i, (name, md5) in enumerate(self.available, start=1):
+                print(f"{i:2d}. {name:<70}  MD5={md5 or 'N/A'}")
+        print("==============================\n")
+
+        # 🧩 Print simulated installed state
+        if not self.installed:
+            print("→ Status: NOT INSTALLED")
+        else:
+            print(f"→ Installed: {self.installed[0]}  MD5={self.installed[1]}")
+
+        if not self.available:
+            self.show_error()
+        elif not self.recommended:
+            print("→ Decision: OS NOT SUPPORTED")
+            self.show_error()
+        elif not self.installed:
+            print(f"→ Decision: NOT INSTALLED (Recommended: {self.recommended[0]})")
+            self.set_state("not_installed")
+        else:
+            installed_tuple = tuple(self.installed)
+            available_tuples = [tuple(a) for a in self.available]
+
+            if installed_tuple in available_tuples:
+                print("→ Decision: INSTALLED (latest version matches)")
+                self.set_state("installed")
+            else:
+                print("→ Decision: UPDATE AVAILABLE (installed not in available list)")
+                self.set_state("update_available")
+
+        self.refresh_btn.setEnabled(True)
+
+    def clear_content(self):
+        """Remove all widgets from content area."""
+        for i in reversed(range(self.content_layout.count())):
+            widget = self.content_layout.itemAt(i).widget()
+            if widget:
+                widget.setParent(None)
+
+    # --- UI STATES ---
+
+    def update_state(self):
+        """Render the current UI state."""
+        self.clear_content()
+        state = self.states[self.current_state]
+
+        if state == "not_installed":
+            self.show_not_installed()
+        elif state == "installed":
+            self.show_installed()
+        elif state == "update_available":
+            self.show_update_available()
+
+    def show_error(self):
+        """Shown when no installer data is available."""
+        self.clear_content()
+        lbl = QtWidgets.QLabel(self.tr("no_installers_found"))
+        lbl.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
+        self.content_layout.addWidget(lbl)
+
+    def show_not_installed(self):
+        recommended_name = self.recommended[0] if self.recommended else "?"
+        lbl = QtWidgets.QLabel(
+            f"{self.tr('no_install_message')}<br>"
+            f"{self.tr('recommended_version')}<br><b>{recommended_name}</b>"
+        )
+        lbl.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
+        self.content_layout.addWidget(lbl)
+
+        btn = QtWidgets.QPushButton(self.tr("install"))
+        btn.setProperty("primary", True)
+        self.content_layout.addWidget(btn)
+
+        combo = QtWidgets.QComboBox()
+        for version, md5 in self.available:
+            combo.addItem(f"{version} (MD5: {md5 or 'N/A'})")
+        self.content_layout.addWidget(combo)
+
+    def show_installed(self):
+        version, md5 = self.installed
+        lbl = QtWidgets.QLabel(
+            f"{self.tr('installed_version')}<br><b>{version}</b><br>MD5: {md5 or 'N/A'}"
+        )
+        lbl.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
+        self.content_layout.addWidget(lbl)
+
+        btn = QtWidgets.QPushButton(self.tr("latest_version_installed"))
+        btn.setEnabled(False)
+        self.content_layout.addWidget(btn)
+
+    def show_update_available(self):
+        version, md5 = self.installed
+        lbl = QtWidgets.QLabel(
+            f"{self.tr('installed_version')}<br><b>{version}</b><br>MD5: {md5 or 'N/A'}"
+        )
+        lbl.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
+        self.content_layout.addWidget(lbl)
+
+        btn = QtWidgets.QPushButton(self.tr("update_digital_signature"))
+        btn.setProperty("primary", True)
+        self.content_layout.addWidget(btn)
+
+        combo = QtWidgets.QComboBox()
+        for version, md5 in self.available:
+            combo.addItem(f"{version} (MD5: {md5 or 'N/A'})")
+        self.content_layout.addWidget(combo)
+
+    def set_state(self, state):
+        if state in self.states:
+            self.current_state = self.states.index(state)
+            self.update_state()