Update OS support

- Add Alpine Linux 3.22 and remove 3.20
- Cleanup

extras/ikev2setup.sh

@@ -103,13 +103,10 @@ EOF
     esac
     if [ "$os_type" = "alpine" ]; then
       os_ver=$(. /etc/os-release && printf '%s' "$VERSION_ID" | cut -d '.' -f 1,2)
-      if [ "$os_ver" != "3.20" ] && [ "$os_ver" != "3.21" ]; then
-        exiterr "This script only supports Alpine Linux 3.20/3.21."
-      fi
     else
       os_ver=$(sed 's/\..*//' /etc/debian_version | tr -dc 'A-Za-z0-9')
       if [ "$os_ver" = 8 ] || [ "$os_ver" = 9 ] || [ "$os_ver" = "stretchsid" ] \
-        || [ "$os_ver" = "bustersid" ]; then
+        || [ "$os_ver" = "bustersid" ] || [ -z "$os_ver" ]; then
 cat 1>&2 <<EOF
 Error: This script requires Debian >= 10 or Ubuntu >= 20.04.
        This version of Ubuntu/Debian is too old and not supported.
@@ -172,7 +169,7 @@ confirm_or_abort() {
 show_header() {
 cat <<'EOF'
 
-IKEv2 Script   Copyright (c) 2020-2025 Lin Song   12 May 2025
+IKEv2 Script   Copyright (c) 2020-2025 Lin Song   1 Sep 2025
 
 EOF
 }

extras/vpnupgrade.sh

@@ -89,12 +89,7 @@ EOF
         exit 1
         ;;
     esac
-    if [ "$os_type" = "alpine" ]; then
-      os_ver=$(. /etc/os-release && printf '%s' "$VERSION_ID" | cut -d '.' -f 1,2)
-      if [ "$os_ver" != "3.20" ] && [ "$os_ver" != "3.21" ]; then
-        exiterr "This script only supports Alpine Linux 3.20/3.21."
-      fi
-    else
+    if [ "$os_type" != "alpine" ]; then
       os_ver=$(sed 's/\..*//' /etc/debian_version | tr -dc 'A-Za-z0-9')
       if [ "$os_ver" = 8 ] || [ "$os_ver" = 9 ] || [ "$os_ver" = "stretchsid" ] \
         || [ "$os_ver" = "bustersid" ] || [ -z "$os_ver" ]; then

extras/vpnupgrade_alpine.sh

@@ -51,9 +51,6 @@ check_os() {
       ;;
   esac
   os_ver=$(. /etc/os-release && printf '%s' "$VERSION_ID" | cut -d '.' -f 1,2)
-  if [ "$os_ver" != "3.20" ] && [ "$os_ver" != "3.21" ]; then
-    exiterr "This script only supports Alpine Linux 3.20/3.21."
-  fi
 }
 
 check_libreswan() {