diff --git a/extras/vpnupgrade.sh b/extras/vpnupgrade.sh
index 713e76a..c760db0 100755
--- a/extras/vpnupgrade.sh
+++ b/extras/vpnupgrade.sh
@@ -14,8 +14,9 @@
 # Attribution required: please include my name in any derivative and let me
 # know how you have improved it!
 
-# Specify which Libreswan version to install. See: https://libreswan.org
-SWAN_VER=4.6
+# (Optional) Specify which Libreswan version to install. See: https://libreswan.org
+# NOTE: If not specified, the latest supported version will be installed.
+SWAN_VER=
 
 ### DO NOT edit below this line ###
 
@@ -91,40 +92,6 @@ EOF
 }
 
 check_libreswan() {
-  if [ "$os_type" != "alpine" ]; then
-    case $SWAN_VER in
-      3.32|4.[1-6])
-        true
-        ;;
-      *)
-cat 1>&2 <<EOF
-Error: Libreswan version '$SWAN_VER' is not supported.
-       This script can install one of these versions:
-       3.32, 4.1-4.5 or 4.6
-EOF
-        exit 1
-        ;;
-    esac
-  else
-    case $SWAN_VER in
-      4.[5-6])
-        true
-        ;;
-      *)
-cat 1>&2 <<EOF
-Error: Libreswan version '$SWAN_VER' is not supported.
-       This script can install one of these versions:
-       4.5 or 4.6
-EOF
-        exit 1
-        ;;
-    esac
-  fi
-
-  if [ "$SWAN_VER" = "3.32" ] && [ "$os_ver" = "11" ]; then
-    exiterr "Libreswan 3.32 is not supported on Debian 11."
-  fi
-
   ipsec_ver=$(/usr/local/sbin/ipsec --version 2>/dev/null)
   if ! printf '%s' "$ipsec_ver" | grep -q "Libreswan"; then
 cat 1>&2 <<'EOF'
diff --git a/extras/vpnupgrade_alpine.sh b/extras/vpnupgrade_alpine.sh
index 90fbb2c..b6d2e9b 100755
--- a/extras/vpnupgrade_alpine.sh
+++ b/extras/vpnupgrade_alpine.sh
@@ -39,7 +39,6 @@ check_vz() {
 
 check_os() {
   os_type=$(lsb_release -si 2>/dev/null)
-  os_arch=$(uname -m | tr -dc 'A-Za-z0-9_-')
   [ -z "$os_type" ] && [ -f /etc/os-release ] && os_type=$(. /etc/os-release && printf '%s' "$ID")
   case $os_type in
     [Aa]lpine)
@@ -139,9 +138,6 @@ EOF
 }
 
 start_setup() {
-  # shellcheck disable=SC2154
-  trap 'dlo=$dl;dl=$LINENO' DEBUG 2>/dev/null
-  trap 'finish $? $((dlo+1))' EXIT
   mkdir -p /opt/src
   cd /opt/src || exit 1
 }
@@ -287,28 +283,6 @@ EOF
   fi
 }
 
-check_swan_ver() {
-  swan_ver_cur=4.6
-  swan_ver_url="https://dl.ls20.com/v1/$os_type/$os_ver/swanverupg?arch=$os_arch&ver1=$swan_ver_old&ver2=$SWAN_VER"
-  [ "$1" != "0" ] && swan_ver_url="$swan_ver_url&e=$2"
-  swan_ver_latest=$(wget -t 3 -T 15 -qO- "$swan_ver_url" | head -n 1)
-  if printf '%s' "$swan_ver_latest" | grep -Eq '^([3-9]|[1-9][0-9]{1,2})(\.([0-9]|[1-9][0-9]{1,2})){1,2}$' \
-    && [ "$1" = "0" ] && [ "$swan_ver_cur" != "$swan_ver_latest" ] \
-    && printf '%s\n%s' "$swan_ver_cur" "$swan_ver_latest" | sort -C -V; then
-cat <<EOF
-Note: A newer version of Libreswan ($swan_ver_latest) is available.
-      To update, run:
-      wget https://git.io/vpnupgrade -O vpnup.sh && sudo sh vpnup.sh
-
-EOF
-  fi
-}
-
-finish() {
-  check_swan_ver "$1" "$2"
-  exit "$1"
-}
-
 vpnupgrade() {
   check_root
   check_vz
diff --git a/extras/vpnupgrade_amzn.sh b/extras/vpnupgrade_amzn.sh
index aec8285..4778247 100755
--- a/extras/vpnupgrade_amzn.sh
+++ b/extras/vpnupgrade_amzn.sh
@@ -32,7 +32,6 @@ check_root() {
 }
 
 check_os() {
-  os_arch=$(uname -m | tr -dc 'A-Za-z0-9_-')
   if ! grep -qs "Amazon Linux release 2" /etc/system-release; then
     exiterr "This script only supports Amazon Linux 2."
   fi
@@ -122,9 +121,6 @@ EOF
 }
 
 start_setup() {
-  # shellcheck disable=SC2154
-  trap 'dlo=$dl;dl=$LINENO' DEBUG 2>/dev/null
-  trap 'finish $? $((dlo+1))' EXIT
   mkdir -p /opt/src
   cd /opt/src || exit 1
 }
@@ -275,28 +271,6 @@ EOF
   fi
 }
 
-check_swan_ver() {
-  swan_ver_cur=4.6
-  swan_ver_url="https://dl.ls20.com/v1/amzn/2/swanverupg?arch=$os_arch&ver1=$swan_ver_old&ver2=$SWAN_VER"
-  [ "$1" != "0" ] && swan_ver_url="$swan_ver_url&e=$2"
-  swan_ver_latest=$(wget -t 3 -T 15 -qO- "$swan_ver_url" | head -n 1)
-  if printf '%s' "$swan_ver_latest" | grep -Eq '^([3-9]|[1-9][0-9]{1,2})(\.([0-9]|[1-9][0-9]{1,2})){1,2}$' \
-    && [ "$1" = "0" ] && [ "$swan_ver_cur" != "$swan_ver_latest" ] \
-    && printf '%s\n%s' "$swan_ver_cur" "$swan_ver_latest" | sort -C -V; then
-cat <<EOF
-Note: A newer version of Libreswan ($swan_ver_latest) is available.
-      To update, run:
-      wget https://git.io/vpnupgrade -O vpnup.sh && sudo sh vpnup.sh
-
-EOF
-  fi
-}
-
-finish() {
-  check_swan_ver "$1" "$2"
-  exit "$1"
-}
-
 vpnupgrade() {
   check_root
   check_os
diff --git a/extras/vpnupgrade_centos.sh b/extras/vpnupgrade_centos.sh
index 62dbdb9..3a18721 100755
--- a/extras/vpnupgrade_centos.sh
+++ b/extras/vpnupgrade_centos.sh
@@ -39,7 +39,6 @@ check_vz() {
 
 check_os() {
   os_type=centos
-  os_arch=$(uname -m | tr -dc 'A-Za-z0-9_-')
   rh_file="/etc/redhat-release"
   if grep -qs "Red Hat" "$rh_file"; then
     os_type=rhel
@@ -140,9 +139,6 @@ EOF
 }
 
 start_setup() {
-  # shellcheck disable=SC2154
-  trap 'dlo=$dl;dl=$LINENO' DEBUG 2>/dev/null
-  trap 'finish $? $((dlo+1))' EXIT
   mkdir -p /opt/src
   cd /opt/src || exit 1
 }
@@ -311,28 +307,6 @@ EOF
   fi
 }
 
-check_swan_ver() {
-  swan_ver_cur=4.6
-  swan_ver_url="https://dl.ls20.com/v1/$os_type/$os_ver/swanverupg?arch=$os_arch&ver1=$swan_ver_old&ver2=$SWAN_VER"
-  [ "$1" != "0" ] && swan_ver_url="$swan_ver_url&e=$2"
-  swan_ver_latest=$(wget -t 3 -T 15 -qO- "$swan_ver_url" | head -n 1)
-  if printf '%s' "$swan_ver_latest" | grep -Eq '^([3-9]|[1-9][0-9]{1,2})(\.([0-9]|[1-9][0-9]{1,2})){1,2}$' \
-    && [ "$1" = "0" ] && [ "$swan_ver_cur" != "$swan_ver_latest" ] \
-    && printf '%s\n%s' "$swan_ver_cur" "$swan_ver_latest" | sort -C -V; then
-cat <<EOF
-Note: A newer version of Libreswan ($swan_ver_latest) is available.
-      To update, run:
-      wget https://git.io/vpnupgrade -O vpnup.sh && sudo sh vpnup.sh
-
-EOF
-  fi
-}
-
-finish() {
-  check_swan_ver "$1" "$2"
-  exit "$1"
-}
-
 vpnupgrade() {
   check_root
   check_vz
diff --git a/extras/vpnupgrade_ubuntu.sh b/extras/vpnupgrade_ubuntu.sh
index 4132fa4..d08e72a 100755
--- a/extras/vpnupgrade_ubuntu.sh
+++ b/extras/vpnupgrade_ubuntu.sh
@@ -39,7 +39,6 @@ check_vz() {
 
 check_os() {
   os_type=$(lsb_release -si 2>/dev/null)
-  os_arch=$(uname -m | tr -dc 'A-Za-z0-9_-')
   [ -z "$os_type" ] && [ -f /etc/os-release ] && os_type=$(. /etc/os-release && printf '%s' "$ID")
   case $os_type in
     [Uu]buntu)
@@ -149,9 +148,6 @@ EOF
 }
 
 start_setup() {
-  # shellcheck disable=SC2154
-  trap 'dlo=$dl;dl=$LINENO' DEBUG 2>/dev/null
-  trap 'finish $? $((dlo+1))' EXIT
   mkdir -p /opt/src
   cd /opt/src || exit 1
 }
@@ -318,28 +314,6 @@ EOF
   fi
 }
 
-check_swan_ver() {
-  swan_ver_cur=4.6
-  swan_ver_url="https://dl.ls20.com/v1/$os_type/$os_ver/swanverupg?arch=$os_arch&ver1=$swan_ver_old&ver2=$SWAN_VER"
-  [ "$1" != "0" ] && swan_ver_url="$swan_ver_url&e=$2"
-  swan_ver_latest=$(wget -t 3 -T 15 -qO- "$swan_ver_url" | head -n 1)
-  if printf '%s' "$swan_ver_latest" | grep -Eq '^([3-9]|[1-9][0-9]{1,2})(\.([0-9]|[1-9][0-9]{1,2})){1,2}$' \
-    && [ "$1" = "0" ] && [ "$swan_ver_cur" != "$swan_ver_latest" ] \
-    && printf '%s\n%s' "$swan_ver_cur" "$swan_ver_latest" | sort -C -V; then
-cat <<EOF
-Note: A newer version of Libreswan ($swan_ver_latest) is available.
-      To update, run:
-      wget https://git.io/vpnupgrade -O vpnup.sh && sudo sh vpnup.sh
-
-EOF
-  fi
-}
-
-finish() {
-  check_swan_ver "$1" "$2"
-  exit "$1"
-}
-
 vpnupgrade() {
   check_root
   check_vz