diff --git a/proxmox/chr_install.sh b/proxmox/chr_install.sh
index b27393c..e972a51 100644
--- a/proxmox/chr_install.sh
+++ b/proxmox/chr_install.sh
@@ -1,84 +1,148 @@
 #!/bin/bash
+#
+# chr_install.sh — deploy a MikroTik CHR (Cloud Hosted Router) as a Proxmox VE VM.
+#
+# Downloads the requested RouterOS CHR image, converts it to qcow2, optionally
+# resizes the disk and creates the VM. Can look up and suggest the current
+# Long-term and Stable RouterOS releases from MikroTik.
 
-#vars
-version="nil"
-vmID="nil"
+set -euo pipefail
 
-echo "############## Start of Script ##############
+#### vars
+TEMP_DIR="/root/temp"
+NODE="$(hostname)"
+MIKROTIK_DL="https://download.mikrotik.com/routeros"
+MIKROTIK_UPG="https://upgrade.mikrotik.com/routeros"
 
-## Checking if temp dir is available..."
-if [ -d /root/temp ] 
-then
+# Defaults for the created VM (override here if needed)
+VM_MEMORY=256
+VM_SOCKETS=1
+VM_CORES=1
+VM_BRIDGE="vmbr0"
+VM_STORAGE="local"
+
+#### helpers
+
+# die MESSAGE — print an error and exit with a failure code.
+die() {
+   echo "-- ERROR: $*" >&2
+   exit 1
+}
+
+# cleanup — remove a half-created image dir if we fail after creating it.
+IMG_DIR=""
+cleanup() {
+   local rc=$?
+   if [ "$rc" -ne 0 ] && [ -n "$IMG_DIR" ] && [ -d "$IMG_DIR" ]; then
+      echo "-- Cleaning up incomplete image dir $IMG_DIR" >&2
+      rm -rf "$IMG_DIR"
+   fi
+}
+trap cleanup EXIT
+
+# valid_version VERSION — accept e.g. 6.40.1, 7.16, 7.16.2
+valid_version() {
+   [[ "$1" =~ ^[0-9]+\.[0-9]+(\.[0-9]+)?$ ]]
+}
+
+# fetch_channel CHANNEL — print the newest version for a RouterOS channel.
+# CHANNEL is one of: stable, long-term, testing. Prints empty on failure.
+fetch_channel() {
+   local channel="$1" line
+   # The NEWESTv7.<channel> file contains: "<version> <unix-timestamp>"
+   line="$(wget -qO- "${MIKROTIK_UPG}/NEWESTv7.${channel}" 2>/dev/null || true)"
+   echo "${line%% *}"
+}
+
+echo "############## Start of Script ##############"
+
+#### 1. temp dir
+echo "## Checking if temp dir is available..."
+if [ -d "$TEMP_DIR" ]; then
    echo "-- Directory exists!"
 else
    echo "-- Creating temp dir!"
-   mkdir /root/temp
+   mkdir -p "$TEMP_DIR" || die "Could not create $TEMP_DIR"
 fi
-# Ask user for version
+
+#### 2. determine version to deploy
 echo "## Preparing for image download and VM creation!"
-read -p "Please input CHR version to deploy (6.38.2, 6.40.1, etc):" version
-# Check if image is available and download if needed
-if [ -f /root/temp/chr-$version.img ] 
-then
+echo "-- Looking up current RouterOS releases from MikroTik..."
+stable_ver="$(fetch_channel stable)"
+lt_ver="$(fetch_channel long-term)"
+
+[ -n "$lt_ver" ]     && echo "   Long-term (recommended): $lt_ver"
+[ -n "$stable_ver" ] && echo "   Stable:                  $stable_ver"
+[ -z "$lt_ver$stable_ver" ] && \
+   echo "   (could not reach MikroTik — enter a version manually)"
+
+# Default to long-term, fall back to stable.
+default_ver="${lt_ver:-$stable_ver}"
+prompt="Please input CHR version to deploy (6.38.2, 6.40.1, etc)"
+[ -n "$default_ver" ] && prompt="$prompt [$default_ver]"
+read -r -p "$prompt: " version
+version="${version:-$default_ver}"
+
+valid_version "$version" || die "Invalid version format: '$version'"
+
+#### 3. download image if needed
+img="$TEMP_DIR/chr-$version.img"
+if [ -f "$img" ]; then
    echo "-- CHR image is available."
 else
    echo "-- Downloading CHR $version image file."
-   cd /root/temp || exit 1
    echo "---------------------------------------------------------------------------"
-   wget https://download.mikrotik.com/routeros/$version/chr-$version.img.zip
-   unzip chr-$version.img.zip
+   wget -O "$TEMP_DIR/chr-$version.img.zip" \
+      "${MIKROTIK_DL}/$version/chr-$version.img.zip" \
+      || die "Download failed for version $version"
+   unzip -o "$TEMP_DIR/chr-$version.img.zip" -d "$TEMP_DIR" \
+      || die "Failed to unzip chr-$version.img.zip"
    echo "---------------------------------------------------------------------------"
 fi
-if [ ! -f /root/temp/chr-$version.img ] 
-then
-   echo "-- Error downloading CHR $version image file!"
-   exit 0
-fi
-# List already existing VM's and ask for vmID
+[ -f "$img" ] || die "CHR $version image file is missing after download!"
+
+#### 4. choose a free VM ID
 echo "== Printing list of VM's on this hypervisor!"
 qm list
 echo "== Printing list of CT's on this hypervisor!"
 pct list
 echo ""
-read -p "Please Enter free vm ID to use:" vmID
+read -r -p "Please enter free VM ID to use: " vmID
 echo ""
-# Create storage dir for VM if needed.
-if [ -f /etc/pve/nodes/pve/qemu-server/$vmID.conf ] 
-then
-   echo "-- VM exists! Try another vm ID!"
-   exit 0
-fi
-if [ -f /etc/pve/nodes/pve/lxc/$vmID.conf ] 
-then
-   echo "-- CT exists! Try another vm ID!"
-   exit 0
-fi
+
+[[ "$vmID" =~ ^[0-9]+$ ]] || die "VM ID must be a number: '$vmID'"
+[ -f "/etc/pve/nodes/$NODE/qemu-server/$vmID.conf" ] && die "VM $vmID exists! Try another ID."
+[ -f "/etc/pve/nodes/$NODE/lxc/$vmID.conf" ]         && die "CT $vmID exists! Try another ID."
+
+#### 5. create image dir + qcow2
+IMG_DIR="/var/lib/vz/images/$vmID"
 echo "-- Creating VM image dir!"
-mkdir /var/lib/vz/images/$vmID
-# Creating qcow2 image for CHR.
-read -p "Please input image size, GB:" imgsize
-echo "-- Converting image to qcow2 format "
-qemu-img convert \
- -f raw \
- -O qcow2 \
- /root/temp/chr-$version.img \
- /var/lib/vz/images/$vmID/vm-$vmID-disk-1.qcow2
-if [ $imgsize -ne 0 ]
-then
-   echo "-- Resize image to $imgsize GB"
-   qemu-img resize \
-   /var/lib/vz/images/$vmID/vm-$vmID-disk-1.qcow2 +${imgsize}G
+mkdir -p "$IMG_DIR" || die "Could not create $IMG_DIR"
+
+read -r -p "Please input extra image size in GB (0 for none): " imgsize
+[[ "$imgsize" =~ ^[0-9]+$ ]] || die "Image size must be a non-negative number: '$imgsize'"
+
+disk="$IMG_DIR/vm-$vmID-disk-0.qcow2"
+echo "-- Converting image to qcow2 format"
+qemu-img convert -f raw -O qcow2 "$img" "$disk" || die "qemu-img convert failed"
+
+if [ "$imgsize" -ne 0 ]; then
+   echo "-- Resizing image by +${imgsize}G"
+   qemu-img resize "$disk" "+${imgsize}G" || die "qemu-img resize failed"
 fi
-# Creating VM
+
+#### 6. create the VM
 echo "-- Creating new CHR VM"
-qm create $vmID \
- --name chr-$version \
- --net0 virtio,bridge=vmbr0 \
- --bootdisk virtio0 \
- --ostype l26 \
- --memory 256 \
- --onboot no \
- --sockets 1 \
- --cores 1 \
- --virtio0 local:$vmID/vm-$vmID-disk-1.qcow2
+qm create "$vmID" \
+   --name "chr-$version" \
+   --net0 "virtio,bridge=$VM_BRIDGE" \
+   --bootdisk virtio0 \
+   --ostype l26 \
+   --memory "$VM_MEMORY" \
+   --onboot no \
+   --sockets "$VM_SOCKETS" \
+   --cores "$VM_CORES" \
+   --virtio0 "$VM_STORAGE:$vmID/vm-$vmID-disk-0.qcow2" \
+   || die "qm create failed"
+
 echo "############## End of Script ##############"