From 8a8933fc3120ebf99be77657f2368dc1227acb6a Mon Sep 17 00:00:00 2001
From: MickLesk <mickey.leskowitz@gmail.com>
Date: Sun, 26 Jul 2026 13:47:21 +0200
Subject: [PATCH] build.func: fix OS mismatch message when script target moved
 to an older OS

---
 misc/build.func | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/misc/build.func b/misc/build.func
index 9b12cc564..5ad76044e 100644
--- a/misc/build.func
+++ b/misc/build.func
@@ -3858,6 +3858,13 @@ check_container_os_guard() {
     return 0
   fi
 
+  local downgraded_target=0
+  if [[ "$cur_os" == "$rec_os" ]] && [[ "$cur_ver" != "$rec_ver" ]]; then
+    if [[ "$(printf '%s\n%s\n' "$cur_ver" "$rec_ver" | sort -V | tail -n1)" == "$cur_ver" ]]; then
+      downgraded_target=1
+    fi
+  fi
+
   case "${var_ignore_os_mismatch:-}" in
   1 | yes | true | on)
     msg_warn "Container OS is ${cur_os} ${cur_ver} but the script recommends ${rec_os} ${rec_ver} — continuing via var_ignore_os_mismatch (may break, no support)."
@@ -3873,10 +3880,19 @@ check_container_os_guard() {
     return 0
   fi
 
+  local mismatch_detail remediation
+  if [[ "$downgraded_target" -eq 1 ]]; then
+    mismatch_detail="Your container runs ${cur_os} ${cur_ver}, which is newer than what this script now targets (${rec_os} ${rec_ver}).\n\nThe target was likely lowered on purpose, e.g. because ${APP:-the app} had problems on newer OS versions - check the GitHub issues for ${APP:-this app} for details.\n\nContinuing on ${cur_ver} often still works, but isn't guaranteed. If you are unsure, ask in our Discord (https://discord.gg/3AnUqsXnmK) before continuing."
+    remediation="This script now targets the older ${rec_os} ${rec_ver}. Check the GitHub issues for ${APP:-this app}, or ask in Discord (https://discord.gg/3AnUqsXnmK) if you are unsure"
+  else
+    mismatch_detail="This container runs ${cur_os} ${cur_ver}, but this script now targets ${rec_os} ${rec_ver}.\n\nUpdating on the older base OS may fail or leave ${APP:-the application} broken (e.g. required runtime versions are not available).\n\nRecommended: upgrade the container OS to ${rec_os} ${rec_ver} first, then run this update again."
+    remediation="Upgrade the container OS to ${rec_os} ${rec_ver} first, then run this update again"
+  fi
+
   if [[ "${PHS_SILENT:-0}" != "1" ]] && command -v whiptail &>/dev/null && [ -t 0 ] && [[ "$TERM" != "dumb" ]]; then
     local choice
     choice=$(whiptail --backtitle "Proxmox VE Helper Scripts" --title "OS VERSION MISMATCH" --menu \
-      "This container runs ${cur_os} ${cur_ver}, but this script now targets ${rec_os} ${rec_ver}.\n\nUpdating on the older base OS may fail or leave ${APP:-the application} broken (e.g. required runtime versions are not available).\n\nRecommended: upgrade the container OS to ${rec_os} ${rec_ver} first, then run this update again.\n\nIf you continue anyway, it may break — no support is provided in that case.\n\nContinue anyway?" \
+      "${mismatch_detail}\n\nIf you continue anyway, it may break — no support is provided in that case.\n\nContinue anyway?" \
       20 70 3 \
       "1" "No  (cancel update)" \
       "2" "Yes (continue this time)" \
@@ -3899,7 +3915,7 @@ check_container_os_guard() {
   fi
 
   msg_error "Container OS ${cur_os} ${cur_ver} does not match the recommended ${rec_os} ${rec_ver} — skipping update."
-  msg_error "Upgrade the container OS to ${rec_os} ${rec_ver} first, then run this update again — or bypass this check (may break, no support) with: echo \"${rec_os} ${rec_ver}\" > ${ignore_file}"
+  msg_error "${remediation} — or bypass this check (may break, no support) with: echo \"${rec_os} ${rec_ver}\" > ${ignore_file}"
   return 1
 }