diff --git a/modules/install_mkagent.sh b/modules/install_mkagent.sh
index c1a3985..1548592 100644
--- a/modules/install_mkagent.sh
+++ b/modules/install_mkagent.sh
@@ -18,18 +18,93 @@
 export VER_install_mkagent="0.1.0"
 export DEP_install_mkagent=""
 
+
+# ------------------------------------------------------------------------------
+# Extract CheckMK version from the server
+get_checkmk_version_from_server()
+{
+    local ip="$1"
+    local site="${2:-$MK_SITE}"
+    local proto out v header
+    local re_version='[0-9]+\.[0-9]+(\.[0-9]+)?p?[0-9]+'
+
+    [[ -n "$MK_VERSION" ]] && { printf '%s' "$MK_VERSION"; return 0; }
+
+    for proto in http https; do
+        # 1) Tentative via version.py (souvent non protégée)
+        if out=$(curl -fsS --max-time 3 "$proto://$ip/$site/check_mk/version.py" 2>/dev/null); then
+            v=$(grep -oE "$re_version" <<<"$out" | head -n1)
+            [[ -n "$v" ]] && { printf '%s' "$v"; return 0; }
+        fi
+
+        # 2) Tentative via login.py (page de connexion)
+        if out=$(curl -fsS --max-time 3 "$proto://$ip/$site/check_mk/login.py" 2>/dev/null); then
+            v=$(grep -oE "$re_version" <<<"$out" | grep -vE '2\.[0-9]{1,3}\.[0-9]{2,3}' | head -n1)
+            [[ -n "$v" ]] && { printf '%s' "$v"; return 0; }
+        fi
+
+        # 3) En-têtes HTTP éventuels
+        header=$(curl -fsSI --max-time 3 "$proto://$ip/$site/" 2>/dev/null || true)
+        if [[ -n "$header" ]]; then
+            v=$(grep -oiE "$re_version" <<<"$header" | head -n1)
+            [[ -n "$v" ]] && { printf '%s' "$v"; return 0; }
+        fi
+
+        # 4) Fallback : page d'accueil, mais filtrer les faux positifs du JS
+        out=$(curl -fsS --max-time 5 "$proto://$ip/$site/" 2>/dev/null || true)
+        if [[ -n "$out" ]]; then
+            # Filtre plus strict : commence par 1.x ou 2.x et max 2 chiffres après le point
+            v=$(grep -oE "$re_version" <<<"$out" \
+                | grep -E '^2\.[0-9]+(\.[0-9]+)?p?[0-9]*$' \
+                | grep -vE '\.[0-9]{3,}' \
+                | head -n1)
+            [[ -n "$v" ]] && { printf '%s-1' "$v"; return 0; }
+        fi
+    done
+
+    return 1
+}
+
 install_mkagent()
 {
-    # Download and install agent
-    wget "$MK_URL" -O /tmp/check-mk-agent_latest_all.deb
-    pkginst /tmp/check-mk-agent_latest_all.deb
-    rm /tmp/check-mk-agent_latest_all.deb
+    local debfile="/tmp/check-mk-agent_latest_all.deb"
+    prnt I "Downloading CheckMK agent from: $MK_URL"
 
-    # Activate correct service depending on system configuration
+    # try primary URL
+    if ! wget -q "$MK_URL" -O "$debfile"; then
+        prnt W "Primary download failed. Attempting to detect server version and fallback..."
+        local mkver
+        mkver=$(get_checkmk_version_from_server "$MK_SERVER_IP" 2>/dev/null || true)
+
+        if [[ -n "$mkver" ]]; then
+            prnt I "Detected Check_MK version: $mkver — building fallback URL"
+            # replace the literal 'latest' token in MK_URL with the detected version
+            local fallback_url
+            fallback_url="${MK_URL/latest/$mkver}"
+            prnt I "Trying fallback URL: $fallback_url"
+            if ! wget -q "$fallback_url" -O "$debfile"; then
+                prnt E "Fallback download with version $mkver failed."
+                die 163
+            fi
+        else
+            prnt E "Unable to detect Check_MK version on $MK_SERVER_IP and primary download failed."
+            die 163
+        fi
+    fi
+
+    # On non-systemd systems, install xinetd before the .deb to avoid postinst failures
+    if ! pidof systemd >/dev/null; then
+        pkginst xinetd
+    fi
+
+    # Install agent package
+    pkginst "$debfile"
+    rm -f "$debfile"
+
+    # Enable service depending on init system
     if pidof systemd >/dev/null; then
         systemctl enable --now check-mk-agent.socket
     else
-        pkginst xinetd
         backup_dist /etc/xinetd.d/check-mk-agent
         install_file cmk/check_mk /etc/xinetd.d/check-mk-agent
         tag_file /etc/xinetd.d/check-mk-agent
@@ -37,29 +112,30 @@ install_mkagent()
         svc_restart xinetd
     fi
 
-    # Install apt plugin (for Debian)
+    # Debian plugin
     if [[ $PKG_MAN == "apt-get" ]]; then
         mkdir -pv /usr/lib/check_mk_agent/plugins/3600
         install_file cmk/mk_apt /usr/lib/check_mk_agent/plugins/3600/mk_apt
     fi
 
-    # Cmk > 2.1, configure agent
+    # Registration (if secret provided)
     if [[ -n $MK_SECRET ]]; then
         local secret
         prnt I "Fetching secret $MK_SECRET..."
         secret=$(fetch_secret "$MK_SECRET")
-
         if [[ -e /var/lib/cmk-agent/cmk-agent-ctl.gz ]]; then
             gunzip -v -f  /var/lib/cmk-agent/cmk-agent-ctl.gz
             chmod -v +x /var/lib/cmk-agent/cmk-agent-ctl
         fi
-        if [[ -e /var/lib/cmk-agent/cmk-agent-ctl ]]; then
+        if [[ -x /var/lib/cmk-agent/cmk-agent-ctl ]]; then
             /var/lib/cmk-agent/cmk-agent-ctl register \
                 --hostname "$HOSTNAME" \
                 --server "$MK_SERVER_IP" \
                 --site "$MK_SITE" \
                 --user "$MK_USER" \
                 --password "$secret"
+        else
+            prnt W "Agent control tool not found; skipping registration."
         fi
         unset secret
     else