diff --git a/README.md b/README.md
index 31bd87b0..9729396b 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@ Features include:
 * Run multiple Minecraft worlds.
 * Start, stop, and restart single or multiple worlds.
 * Create, delete, disable, and enable worlds.
-* Includes support for additional server types: [Forge](http://www.minecraftforge.net/),
+* Includes support for additional server types: [PaperMC](http://papermc.io), [Forge](http://www.minecraftforge.net/),
 [BungeeCord](http://www.spigotmc.org/wiki/bungeecord/),
 [SpigotMC](http://www.spigotmc.org/wiki/spigot/), etc.
 * Users automatically notified of important server events.
diff --git a/msctl b/msctl
index 5ec3a222..0384533f 100644
--- a/msctl
+++ b/msctl
@@ -194,15 +194,27 @@ mscs_defaults() {
 ; Location of world files.
 # mscs-worlds-location=/opt/mscs/worlds
 
+; Location of version JSON cache files.
+# mscs-versions-location=/opt/mscs/versions
+
 ; URL to download the version_manifest.json file.
 # mscs-versions-url=https://launchermeta.mojang.com/mc/game/version_manifest.json
 
 ; Location of the version_manifest.json file.
-# mscs-versions-json=/opt/mscs/version_manifest.json
+# mscs-versions-json=/opt/mscs/versions/version_manifest.json
 
 ; Length in minutes to keep the version_manifest.json file before updating.
 # mscs-versions-duration=30
 
+; URL to download the PaperMC project information file.
+# mscs-paper-versions-url=https://fill.papermc.io/v3/projects/paper
+
+; Location of the PaperMC project information file.
+# mscs-paper-project-json=/opt/mscs/versions/paper_project.json
+
+; Default PaperMC build channel (STABLE, BETA, or ALPHA).
+# mscs-default-paper-channel=STABLE
+
 ; Length in minutes to keep lock files before removing.
 # mscs-lockfile-duration=1440
 
@@ -774,6 +786,7 @@ setServerPropertiesValue() {
 # Update the version_manifest.json file.
 # ---------------------------------------------------------------------------
 updateVersionsJSON() {
+  mkdir -p "$VERSIONS_LOCATION"
   if [ -s $VERSIONS_JSON ]; then
     # Make a backup copy of the version_manifest.json file.
     cp -p "$VERSIONS_JSON" "$VERSIONS_JSON.bak"
@@ -802,6 +815,218 @@ updateVersionsJSON() {
   fi
 }
 
+# ---------------------------------------------------------------------------
+# Update the paper_project.json file.
+# ---------------------------------------------------------------------------
+updatePaperProjectJSON() {
+  mkdir -p "$VERSIONS_LOCATION"
+  if [ -s "$PAPER_PROJECT_JSON" ]; then
+    # Make a backup copy of the paper_project.json file.
+    cp -p "$PAPER_PROJECT_JSON" "$PAPER_PROJECT_JSON.bak"
+    # Delete the paper_project.json file if it is old.
+    find "$PAPER_PROJECT_JSON" -mmin +"$VERSIONS_DURATION" -delete >/dev/null 2>&1
+    if [ -s "$PAPER_PROJECT_JSON" ]; then
+      printf "The cached copy of the PaperMC project information is up to date.\n"
+      printf "Use the force-update option to ensure a new copy is downloaded.\n"
+    else
+      printf "The PaperMC project information cache was out of date, it has been removed.\n"
+    fi
+  fi
+  # Download the paper_project.json file if it does not exist.
+  if [ ! -s "$PAPER_PROJECT_JSON" ]; then
+    printf "Downloading current PaperMC project information.\n"
+    $WGET --no-use-server-timestamps \
+      --header="User-Agent: mscs/1.0 (https://github.com/MinecraftServerControl/mscs)" \
+      -qO "$PAPER_PROJECT_JSON" "$PAPER_VERSIONS_URL"
+    if [ $? -ne 0 ]; then
+      if [ -s "$PAPER_PROJECT_JSON.bak" ]; then
+        printf "Error downloading the PaperMC project information, using a backup.\n"
+        cp -p "$PAPER_PROJECT_JSON.bak" "$PAPER_PROJECT_JSON"
+      else
+        printf "Error downloading the PaperMC project information, exiting.\n"
+        exit 1
+      fi
+    fi
+  fi
+}
+
+# ---------------------------------------------------------------------------
+# Get the current PaperMC version number.
+#
+# @param 1 The world server.
+# @return The current PaperMC version number.
+# ---------------------------------------------------------------------------
+getCurrentPaperVersion() {
+  local BUILDS_JSON BUILDS_URL CHANNEL HAS_CHANNEL VERSION VERSIONS
+  mkdir -p "$VERSIONS_LOCATION"
+  CHANNEL=$(getMSCSValue "$1" "mscs-paper-channel" "$DEFAULT_PAPER_CHANNEL")
+  # Get all candidate versions from newest family first, skipping pre/rc.
+  VERSIONS=$(cat "$PAPER_PROJECT_JSON" | $PERL -0777 -ne '
+    use JSON;
+    $json = decode_json ($_);
+    my @families = sort {
+      my @av = split /\./, $a; my @bv = split /\./, $b;
+      for my $i (0..($#av > $#bv ? $#av : $#bv)) {
+        my $c = ($bv[$i]//0) <=> ($av[$i]//0); return $c if $c;
+      } 0;
+    } keys %{$json->{versions}};
+    for my $family (@families) {
+      my ($v) = grep { !/-(pre|rc)\d*$/i } @{$json->{versions}{$family}};
+      next unless defined $v;
+      $v =~ s/[\s#%*+?^\${}()|[\]\\]/-/g;
+      print "$v\n";
+    }
+  ')
+  # Find the newest version that has a build in the desired channel.
+  for VERSION in $VERSIONS; do
+    BUILDS_JSON="$VERSIONS_LOCATION/paper_builds_$VERSION.json"
+    BUILDS_URL="$PAPER_VERSIONS_URL/versions/$VERSION/builds"
+    # Download builds JSON for this version if not cached.
+    if [ ! -s "$BUILDS_JSON" ]; then
+      $WGET --no-use-server-timestamps \
+        --header="User-Agent: mscs/1.0 (https://github.com/MinecraftServerControl/mscs)" \
+        -qO "$BUILDS_JSON" "$BUILDS_URL" 2>/dev/null || rm -f "$BUILDS_JSON"
+    fi
+    if [ -s "$BUILDS_JSON" ]; then
+      # Verify this version has a build in the desired channel.
+      HAS_CHANNEL=$(cat "$BUILDS_JSON" | $PERL -0777 -sne '
+        use JSON;
+        my $builds = decode_json($_);
+        my ($b) = grep { $_->{channel} eq $channel } @{$builds};
+        print "yes" if defined $b;
+      ' -- -channel="$CHANNEL")
+      if [ "$HAS_CHANNEL" = "yes" ]; then
+        printf "%s" "$VERSION"
+        return
+      fi
+    else
+      # Builds JSON unavailable (download failed); assume this version is valid.
+      printf "%s" "$VERSION"
+      return
+    fi
+  done
+  printf "Error detecting the current PaperMC version.\n"
+  exit 1
+}
+
+# ---------------------------------------------------------------------------
+# Update the paper_builds_VERSION.json file for the world.
+#
+# @param 1 The world server.
+# ---------------------------------------------------------------------------
+updatePaperBuildsJSON() {
+  local PAPER_BUILDS_JSON PAPER_BUILDS_URL SERVER_VERSION
+  mkdir -p "$VERSIONS_LOCATION"
+  SERVER_VERSION=$(getServerVersion "$1")
+  if [ $? -ne 0 ]; then
+    printf "%s\n" "$SERVER_VERSION"
+    exit 1
+  fi
+  PAPER_BUILDS_JSON="$VERSIONS_LOCATION/paper_builds_$SERVER_VERSION.json"
+  PAPER_BUILDS_URL="$PAPER_VERSIONS_URL/versions/$SERVER_VERSION/builds"
+  if [ -s "$PAPER_BUILDS_JSON" ]; then
+    # Make a backup copy of the paper_builds_VERSION.json file.
+    cp -p "$PAPER_BUILDS_JSON" "$PAPER_BUILDS_JSON.bak"
+    # Delete the paper_builds_VERSION.json file if it is old.
+    find "$PAPER_BUILDS_JSON" -mmin +"$VERSIONS_DURATION" -delete >/dev/null 2>&1
+    if [ -s "$PAPER_BUILDS_JSON" ]; then
+      printf "The cached copy of the PaperMC build list is up to date.\n"
+      printf "Use the force-update option to ensure a new copy is downloaded.\n"
+    else
+      printf "The PaperMC build list cache was out of date, it has been removed.\n"
+    fi
+  fi
+  # Download the paper_builds_VERSION.json file if it does not exist.
+  if [ ! -s "$PAPER_BUILDS_JSON" ]; then
+    printf "Downloading current PaperMC build list.\n"
+    $WGET --no-use-server-timestamps \
+      --header="User-Agent: mscs/1.0 (https://github.com/MinecraftServerControl/mscs)" \
+      -qO "$PAPER_BUILDS_JSON" "$PAPER_BUILDS_URL"
+    if [ $? -ne 0 ]; then
+      if [ -s "$PAPER_BUILDS_JSON.bak" ]; then
+        printf "Error downloading the PaperMC build list, using a backup.\n"
+        cp -p "$PAPER_BUILDS_JSON.bak" "$PAPER_BUILDS_JSON"
+      else
+        printf "Error downloading the PaperMC build list, exiting.\n"
+        exit 1
+      fi
+    fi
+  fi
+}
+
+# ---------------------------------------------------------------------------
+# Get the download URL for a PaperMC server version.
+#
+# @param 1 The world server.
+# @return The download URL for the PaperMC server.
+# ---------------------------------------------------------------------------
+getPaperServerURL() {
+  local CHANNEL PAPER_BUILDS_JSON SERVER_VERSION
+  SERVER_VERSION=$(getServerVersion "$1")
+  if [ $? -ne 0 ]; then
+    printf "%s\n" "$SERVER_VERSION"
+    exit 1
+  fi
+  CHANNEL=$(getMSCSValue "$1" "mscs-paper-channel" "$DEFAULT_PAPER_CHANNEL")
+  PAPER_BUILDS_JSON="$VERSIONS_LOCATION/paper_builds_$SERVER_VERSION.json"
+  cat "$PAPER_BUILDS_JSON" | $PERL -0777 -sne '
+    use JSON;
+    my $builds = decode_json ($_);
+    my ($b) = grep { $_->{channel} eq "$channel" } @{$builds};
+    print $b->{downloads}{"server:default"}{url};
+  ' -- -channel="$CHANNEL"
+}
+
+# ---------------------------------------------------------------------------
+# Get the sha256sum for a PaperMC server version.
+#
+# @param 1 The world server.
+# @return The sha256sum for the PaperMC server.
+# ---------------------------------------------------------------------------
+getPaperServerChecksum() {
+  local CHANNEL PAPER_BUILDS_JSON SERVER_VERSION
+  SERVER_VERSION=$(getServerVersion "$1")
+  if [ $? -ne 0 ]; then
+    printf "%s\n" "$SERVER_VERSION"
+    exit 1
+  fi
+  CHANNEL=$(getMSCSValue "$1" "mscs-paper-channel" "$DEFAULT_PAPER_CHANNEL")
+  PAPER_BUILDS_JSON="$VERSIONS_LOCATION/paper_builds_$SERVER_VERSION.json"
+  cat "$PAPER_BUILDS_JSON" | $PERL -0777 -sne '
+    use JSON;
+    my $builds = decode_json ($_);
+    my ($b) = grep { $_->{channel} eq "$channel" } @{$builds};
+    print $b->{downloads}{"server:default"}{checksums}{sha256};
+  ' -- -channel="$CHANNEL"
+}
+
+# ---------------------------------------------------------------------------
+# Update the modded server build information for the world.
+#
+# @param 1 The world server.
+# ---------------------------------------------------------------------------
+updateModdedServerBuilds() {
+  case "$(getMSCSValue "$1" "mscs-server-type" "vanilla")" in
+    papermc)
+      updatePaperProjectJSON
+      updatePaperBuildsJSON "$1"
+      ;;
+  esac
+}
+
+# ---------------------------------------------------------------------------
+# Get the current version number for the server type of the world.
+#
+# @param 1 The world server.
+# @return The current version number.
+# ---------------------------------------------------------------------------
+getServerCurrentVersion() {
+  case "$(getMSCSValue "$1" "mscs-server-type" "vanilla")" in
+    papermc) getCurrentPaperVersion "$1" ;;
+    *)       getCurrentMinecraftVersion "$1" ;;
+  esac
+}
+
 # ---------------------------------------------------------------------------
 # Get the current Minecraft version number.
 #
@@ -1015,7 +1240,7 @@ getClientURL() {
 # ---------------------------------------------------------------------------
 getServerVersion() {
   local CURRENT_VERSION
-  CURRENT_VERSION=$(getCurrentMinecraftVersion "$1")
+  CURRENT_VERSION=$(getServerCurrentVersion "$1")
   if [ $? -ne 0 ]; then
     printf "$CURRENT_VERSION\n"
     exit 1
@@ -1036,8 +1261,8 @@ getServerVersion() {
 # @return SERVER_JAR
 # ---------------------------------------------------------------------------
 getServerJar() {
-  local CURRENT_VERSION SERVER_VERSION SERVER_JAR
-  CURRENT_VERSION=$(getCurrentMinecraftVersion "$1")
+  local CURRENT_VERSION DEFAULT_JAR SERVER_TYPE SERVER_VERSION
+  CURRENT_VERSION=$(getServerCurrentVersion "$1")
   if [ $? -ne 0 ]; then
     printf "$CURRENT_VERSION\n"
     exit 1
@@ -1047,8 +1272,15 @@ getServerJar() {
     printf "$SERVER_VERSION\n"
     exit 1
   fi
+  # Choose the default jar name based on the server type.
+  SERVER_TYPE=$(getMSCSValue "$1" "mscs-server-type" "vanilla")
+  case "$SERVER_TYPE" in
+    papermc) DEFAULT_JAR='paper.$SERVER_VERSION.jar' ;;
+    # forge)  DEFAULT_JAR='forge-$SERVER_VERSION.jar' ;;
+    *)       DEFAULT_JAR="$DEFAULT_SERVER_JAR" ;;
+  esac
   # Get the server jar, use the default value if not provided.
-  getMSCSValue "$1" "mscs-server-jar" "$DEFAULT_SERVER_JAR" |
+  getMSCSValue "$1" "mscs-server-jar" "$DEFAULT_JAR" |
     $PERL -sne '
     $_ =~ s/\$CURRENT_VERSION/$current_version/g;
     $_ =~ s/\$SERVER_VERSION/$server_version/g;
@@ -1064,7 +1296,7 @@ getServerJar() {
 # ---------------------------------------------------------------------------
 getServerLocation() {
   local CURRENT_VERSION SERVER_VERSION
-  CURRENT_VERSION=$(getCurrentMinecraftVersion "$1")
+  CURRENT_VERSION=$(getServerCurrentVersion "$1")
   if [ $? -ne 0 ]; then
     printf "$CURRENT_VERSION\n"
     exit 1
@@ -1091,7 +1323,7 @@ getServerLocation() {
 # ---------------------------------------------------------------------------
 getServerURL() {
   local CURRENT_VERSION SERVER_VERSION URL
-  CURRENT_VERSION=$(getCurrentMinecraftVersion "$1")
+  CURRENT_VERSION=$(getServerCurrentVersion "$1")
   if [ $? -ne 0 ]; then
     printf "$CURRENT_VERSION\n"
     exit 1
@@ -1109,9 +1341,13 @@ getServerURL() {
     print;
   ' -- -current_version="$CURRENT_VERSION" -server_version="$SERVER_VERSION")
   # If the download URL was not specified, extract it from the version
-  # manifest.
+  # manifest or server-type-specific source.
   if [ -z "$URL" ]; then
-    URL=$(getMinecraftVersionDownloadURL $SERVER_VERSION 'server')
+    case "$(getMSCSValue "$1" "mscs-server-type" "vanilla")" in
+      papermc) URL=$(getPaperServerURL "$1") ;;
+      # forge)  URL=$(getForgeServerURL "$1") ;;
+      *)       URL=$(getMinecraftVersionDownloadURL $SERVER_VERSION 'server') ;;
+    esac
   fi
   printf "$URL"
 }
@@ -1816,7 +2052,8 @@ updateClientSoftware() {
 # @param 1 The world server to update.
 # ---------------------------------------------------------------------------
 updateServerSoftware() {
-  local SERVER_JAR SERVER_LOCATION SERVER_URL SERVER_VERSION SHA1 SHA1_FILE
+  local SERVER_JAR SERVER_LOCATION SERVER_TYPE SERVER_URL SERVER_VERSION
+  local SHA1 SHA1_FILE SHA256 SHA256_FILE
   SERVER_JAR=$(getServerJar "$1")
   if [ $? -ne 0 ]; then
     printf "$SERVER_JAR\n"
@@ -1839,6 +2076,18 @@ updateServerSoftware() {
   fi
   # Make sure the server software directory exists.
   mkdir -p "$SERVER_LOCATION"
+  # For PaperMC, re-download if the installed JAR does not match the latest build.
+  if [ "$(getMSCSValue "$1" "mscs-server-type" "vanilla")" = "papermc" ] &&
+     [ -s "$SERVER_LOCATION/$SERVER_JAR" ]; then
+    SHA256=$(getPaperServerChecksum "$1")
+    if [ -n "$SHA256" ]; then
+      SHA256_FILE=$(sha256sum "$SERVER_LOCATION/$SERVER_JAR" | cut -d ' ' -f1)
+      if [ "$SHA256" != "$SHA256_FILE" ]; then
+        printf "Newer PaperMC build available, removing outdated server JAR.\n"
+        rm -f "$SERVER_LOCATION/$SERVER_JAR"
+      fi
+    fi
+  fi
   # Download the server jar if it is missing.
   if [ ! -s "$SERVER_LOCATION/$SERVER_JAR" ]; then
     # Download the Minecraft server software.
@@ -1848,15 +2097,31 @@ updateServerSoftware() {
       printf "Error updating the Minecraft server software.\n"
       exit 1
     fi
-    SHA1=$(getMinecraftVersionDownloadSHA1 $SERVER_VERSION 'server')
-    if [ -z $SHA1 ]; then
-      printf "Error retrieving the sha1 for the Minecraft server software.\n"
-      exit 1
-    fi
-    SHA1_FILE=$(sha1sum $SERVER_LOCATION/$SERVER_JAR | cut -d ' ' -f1)
-    if [ $SHA1 != "$SHA1_FILE" ]; then
-      printf "Error verifying the sha1 for the Minecraft server software.\n"
-    fi
+    SERVER_TYPE=$(getMSCSValue "$1" "mscs-server-type" "vanilla")
+    case "$SERVER_TYPE" in
+      papermc)
+        SHA256=$(getPaperServerChecksum "$1")
+        if [ -z "$SHA256" ]; then
+          printf "Error retrieving the sha256 for the Paper server software.\n"
+          exit 1
+        fi
+        SHA256_FILE=$(sha256sum "$SERVER_LOCATION/$SERVER_JAR" | cut -d ' ' -f1)
+        if [ "$SHA256" != "$SHA256_FILE" ]; then
+          printf "Error verifying the sha256 for the Paper server software.\n"
+        fi
+        ;;
+      *)
+        SHA1=$(getMinecraftVersionDownloadSHA1 "$SERVER_VERSION" 'server')
+        if [ -z "$SHA1" ]; then
+          printf "Error retrieving the sha1 for the Minecraft server software.\n"
+          exit 1
+        fi
+        SHA1_FILE=$(sha1sum "$SERVER_LOCATION/$SERVER_JAR" | cut -d ' ' -f1)
+        if [ "$SHA1" != "$SHA1_FILE" ]; then
+          printf "Error verifying the sha1 for the Minecraft server software.\n"
+        fi
+        ;;
+    esac
   fi
 }
 
@@ -2549,6 +2814,8 @@ fi
 LOCATION=$(getDefaultsValue 'mscs-location' $HOME'/mscs')
 # Override with command-line location option.
 [ -n "$LOCATION_CL" ] && LOCATION="$LOCATION_CL"
+# The location to store version JSON files.
+VERSIONS_LOCATION=$(getDefaultsValue 'mscs-versions-location' $LOCATION'/versions')
 
 # Global Server Configuration
 # ---------------------------------------------------------------------------
@@ -2557,6 +2824,12 @@ LOCATION=$(getDefaultsValue 'mscs-location' $HOME'/mscs')
 # ---------------------------------------------------------------------------
 MINECRAFT_VERSIONS_URL=$(getDefaultsValue 'mscs-versions-url' 'https://launchermeta.mojang.com/mc/game/version_manifest.json')
 
+# PaperMC Versions information
+# ---------------------------------------------------------------------------
+PAPER_VERSIONS_URL=$(getDefaultsValue 'mscs-paper-versions-url' 'https://fill.papermc.io/v3/projects/paper')
+PAPER_PROJECT_JSON=$(getDefaultsValue 'mscs-paper-project-json' $VERSIONS_LOCATION'/paper_project.json')
+DEFAULT_PAPER_CHANNEL=$(getDefaultsValue 'mscs-default-paper-channel' 'STABLE')
+
 # Minecraft Server Settings
 # ---------------------------------------------------------------------------
 # Settings used if not provided in the world's mscs.properties file.
@@ -2598,6 +2871,8 @@ DEFAULT_RESTART_AFTER_CRASH=$(getDefaultsValue 'mscs-default-restart-after-crash
 #   mscs-server-location - Assign the location of the server .jar file.
 #   mscs-server-command  - Assign the command to run for the server.
 #   mscs-restart-after-crash - Restart the server after a crash (default disabled).
+#   mscs-server-type     - Assign the server type (vanilla, papermc).
+#   mscs-paper-channel   - Assign the PaperMC build channel (STABLE, BETA, ALPHA).
 #
 # Like above, the following variables may be used in some of the key values:
 #   $JAVA                - The Java virtual machine.
@@ -2628,13 +2903,15 @@ DEFAULT_RESTART_AFTER_CRASH=$(getDefaultsValue 'mscs-default-restart-after-crash
 #   mscs-server-location=/opt/mscs/server
 #   mscs-server-command=$JAVA -Xms$INITIAL_MEMORY -Xmx$MAXIMUM_MEMORY $JVM_ARGS -jar $SERVER_LOCATION/$SERVER_JAR $SERVER_ARGS
 #   mscs-restart-after-crash=false
+#   mscs-server-type=vanilla
+#   mscs-paper-channel=STABLE
 
 # World (Server Instance) Configuration
 # ---------------------------------------------------------------------------
 # The location to store files for each world server.
 WORLDS_LOCATION=$(getDefaultsValue 'mscs-worlds-location' $LOCATION'/worlds')
 # The location to store the version_manifest.json file.
-VERSIONS_JSON=$(getDefaultsValue 'mscs-versions-json' $LOCATION'/version_manifest.json')
+VERSIONS_JSON=$(getDefaultsValue 'mscs-versions-json' $VERSIONS_LOCATION'/version_manifest.json')
 # The duration (in minutes) to keep the version_manifest.json file before updating.
 VERSIONS_DURATION=$(getDefaultsValue 'mscs-versions-duration' '30')
 # The duration (in minutes) to keep lock files before removing.
@@ -2739,6 +3016,10 @@ case "$COMMAND" in
         fi
       done
     fi
+    # Grab the latest modded server build information.
+    for WORLD in $WORLDS; do
+      updateModdedServerBuilds "$WORLD"
+    done
     # Start each world requested, if not already running.
     printf "Starting Minecraft Server:"
     for WORLD in $WORLDS; do
@@ -2830,6 +3111,10 @@ case "$COMMAND" in
       printf "Unable to restart worlds: no enabled worlds found.\n"
       exit 1
     fi
+    # Grab the latest modded server build information.
+    for WORLD in $WORLDS; do
+      updateModdedServerBuilds "$WORLD"
+    done
     # Restart each world requested, start those not already
     # running.
     printf "Restarting Minecraft Server:"
@@ -3036,6 +3321,10 @@ case "$COMMAND" in
       printf "Unable to enable worlds: no disabled worlds found.\n"
       exit 1
     fi
+    # Grab the latest modded server build information.
+    for WORLD in $WORLDS; do
+      updateModdedServerBuilds "$WORLD"
+    done
     printf "Enabling Minecraft world:"
     # Enable the world(s).
     for WORLD in $WORLDS; do
@@ -3388,7 +3677,14 @@ case "$COMMAND" in
         cp -fp "$VERSIONS_JSON" "$VERSIONS_JSON.bak"
         printf "Removing cached version manifest.\n"
       fi
-      rm -f $VERSIONS_JSON
+      rm -f "$VERSIONS_JSON"
+      # Remove cached PaperMC project information.
+      if [ -s "$PAPER_PROJECT_JSON" ]; then
+        cp -fp "$PAPER_PROJECT_JSON" "$PAPER_PROJECT_JSON.bak"
+        printf "Removing cached PaperMC project information.\n"
+      fi
+      rm -f "$PAPER_PROJECT_JSON"
+      rm -f "$VERSIONS_LOCATION"/paper_builds_*.json
     fi
     # Grab the latest version information.
     updateVersionsJSON
@@ -3411,6 +3707,10 @@ case "$COMMAND" in
       printf "Unable to update worlds: no enabled worlds found.\n"
       exit 1
     fi
+    # Grab the latest modded server build information.
+    for WORLD in $WORLDS; do
+      updateModdedServerBuilds "$WORLD"
+    done
     # Stop all of the world servers and backup the worlds.
     RUNNING=
     printf "Stopping Minecraft Server:"
diff --git a/tests/mscs-config-ops.sh b/tests/mscs-config-ops.sh
new file mode 100644
index 00000000..317f98de
--- /dev/null
+++ b/tests/mscs-config-ops.sh
@@ -0,0 +1,124 @@
+#!/bin/sh
+
+_cfg=/tmp/mscs-configtest.properties
+
+# clean start
+rm -f "$_cfg"
+
+# --- getValue ---
+
+# key present returns value
+printf "mykey=myvalue\n" > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "default")
+if [ "$got" != "myvalue" ]; then
+  terr "getValue key present: got '$got' want 'myvalue'"
+fi
+
+# key absent returns default
+printf "otherkey=othervalue\n" > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "thedefault")
+if [ "$got" != "thedefault" ]; then
+  terr "getValue key absent: got '$got' want 'thedefault'"
+fi
+
+# file does not exist returns default
+rm -f "$_cfg"
+got=$(getValue "$_cfg" "mykey" "thedefault")
+if [ "$got" != "thedefault" ]; then
+  terr "getValue no file: got '$got' want 'thedefault'"
+fi
+
+# empty value returns default ([ -n "$KEY" ] && [ -n "$VALUE" ] requires both non-empty)
+printf "mykey=\n" > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "thedefault")
+if [ "$got" != "thedefault" ]; then
+  terr "getValue empty value: got '$got' want 'thedefault'"
+fi
+
+# key matching is case-insensitive
+printf "MYKEY=myvalue\n" > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "default")
+if [ "$got" != "myvalue" ]; then
+  terr "getValue case-insensitive: got '$got' want 'myvalue'"
+fi
+
+# hash comment lines are ignored
+printf "# mykey=commented\n" > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "default")
+if [ "$got" != "default" ]; then
+  terr "getValue hash comment: got '$got' want 'default'"
+fi
+
+# semicolon comment lines are ignored
+printf "; mykey=commented\n" > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "default")
+if [ "$got" != "default" ]; then
+  terr "getValue semicolon comment: got '$got' want 'default'"
+fi
+
+# double quotes are stripped from value
+printf 'mykey="quoted-value"\n' > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "default")
+if [ "$got" != "quoted-value" ]; then
+  terr "getValue double-quote strip: got '$got' want 'quoted-value'"
+fi
+
+# single quotes are stripped from value
+printf "mykey='quoted-value'\n" > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "default")
+if [ "$got" != "quoted-value" ]; then
+  terr "getValue single-quote strip: got '$got' want 'quoted-value'"
+fi
+
+# spaces around = are handled
+printf "mykey = spaced-value\n" > "$_cfg"
+got=$(getValue "$_cfg" "mykey" "default")
+if [ "$got" != "spaced-value" ]; then
+  terr "getValue spaces around =: got '$got' want 'spaced-value'"
+fi
+
+# default with leading hyphen is returned verbatim (printf -- prevents flag misinterpretation)
+rm -f "$_cfg"
+got=$(getValue "$_cfg" "mykey" "-Dfoo=bar")
+if [ "$got" != "-Dfoo=bar" ]; then
+  terr "getValue hyphen default: got '$got' want '-Dfoo=bar'"
+fi
+
+# --- setValue ---
+
+# new key is appended to an empty file
+: > "$_cfg"
+setValue "$_cfg" "newkey" "newvalue"
+if ! grep -qs "^newkey=newvalue$" "$_cfg"; then
+  terr "setValue append: file contents: $(cat "$_cfg")"
+fi
+
+# existing key is updated in-place
+printf "mykey=old\n" > "$_cfg"
+setValue "$_cfg" "mykey" "new"
+got=$(getValue "$_cfg" "mykey" "default")
+if [ "$got" != "new" ]; then
+  terr "setValue update: got '$got' want 'new'"
+fi
+
+# other keys are preserved when one key is updated
+printf "key1=a\nkey2=b\n" > "$_cfg"
+setValue "$_cfg" "key1" "x"
+got=$(getValue "$_cfg" "key2" "default")
+if [ "$got" != "b" ]; then
+  terr "setValue preserves others: key2 got '$got' want 'b'"
+fi
+
+# file is created when it does not exist
+rm -f "$_cfg"
+setValue "$_cfg" "newkey" "newvalue"
+if [ ! -f "$_cfg" ]; then
+  terr "setValue creates file: file not found at $_cfg"
+fi
+got=$(getValue "$_cfg" "newkey" "default")
+if [ "$got" != "newvalue" ]; then
+  terr "setValue creates file value: got '$got' want 'newvalue'"
+fi
+
+# clean up
+rm -f "$_cfg"
diff --git a/tests/mscs-papermc.sh b/tests/mscs-papermc.sh
new file mode 100644
index 00000000..70c0e75c
--- /dev/null
+++ b/tests/mscs-papermc.sh
@@ -0,0 +1,131 @@
+#!/bin/sh
+
+_paper_test_location=/tmp/mscs-papertest
+mkdir -p "$_paper_test_location"
+_orig_paper_project_json="${PAPER_PROJECT_JSON}"
+_orig_location="${LOCATION}"
+_orig_versions_location="${VERSIONS_LOCATION}"
+PAPER_PROJECT_JSON="$_paper_test_location/paper_project.json"
+LOCATION="$_paper_test_location"
+VERSIONS_LOCATION="$_paper_test_location"
+
+# Fixture: project JSON with mixed releases and pre-releases across two families
+cat > "$PAPER_PROJECT_JSON" << 'EOF'
+{
+  "versions": {
+    "1.20": ["1.20.4", "1.20.2"],
+    "1.21": ["1.21.4", "1.21.1", "1.21-pre2", "1.21-rc1"]
+  }
+}
+EOF
+
+# Fixture: builds JSON for the versions getCurrentPaperVersion will check
+cat > "$_paper_test_location/paper_builds_1.21.4.json" << 'EOF'
+[{"channel": "STABLE", "downloads": {"server:default": {"url": "https://test.example.com/paper-1.21.4-100.jar", "checksums": {"sha256": "stablechecksum456"}}}}]
+EOF
+
+# getCurrentPaperVersion returns the latest non-pre-release from the latest family
+got=$(getCurrentPaperVersion "$testworld")
+want="1.21.4"
+if [ "$got" != "$want" ]; then
+  terr "getCurrentPaperVersion: got '$got' want '$want'"
+fi
+
+# getCurrentPaperVersion skips pre-releases even when they appear before a release
+cat > "$PAPER_PROJECT_JSON" << 'EOF'
+{
+  "versions": {
+    "1.21": ["1.21-rc2", "1.21.4", "1.21.1"]
+  }
+}
+EOF
+got=$(getCurrentPaperVersion "$testworld")
+want="1.21.4"
+if [ "$got" != "$want" ]; then
+  terr "getCurrentPaperVersion pre-release-first: got '$got' want '$want'"
+fi
+
+# Fixture: builds JSON with STABLE and BETA channels
+cat > "$_paper_test_location/paper_builds_1.21.4.json" << 'EOF'
+[
+  {
+    "channel": "BETA",
+    "downloads": {
+      "server:default": {
+        "url": "https://test.example.com/paper-1.21.4-101.jar",
+        "checksums": { "sha256": "betachecksum123" }
+      }
+    }
+  },
+  {
+    "channel": "STABLE",
+    "downloads": {
+      "server:default": {
+        "url": "https://test.example.com/paper-1.21.4-100.jar",
+        "checksums": { "sha256": "stablechecksum456" }
+      }
+    }
+  }
+]
+EOF
+
+# getPaperServerURL returns the URL for the STABLE channel (default)
+(
+  getServerVersion() { printf "1.21.4"; }
+  > "$propfile"
+  got=$(getPaperServerURL "$testworld")
+  want="https://test.example.com/paper-1.21.4-100.jar"
+  if [ "$got" != "$want" ]; then
+    terr "getPaperServerURL STABLE: got '$got' want '$want'"
+  fi
+)
+
+# getPaperServerURL returns the URL for the BETA channel when configured
+(
+  getServerVersion() { printf "1.21.4"; }
+  printf "mscs-paper-channel=BETA\n" > "$propfile"
+  got=$(getPaperServerURL "$testworld")
+  want="https://test.example.com/paper-1.21.4-101.jar"
+  if [ "$got" != "$want" ]; then
+    terr "getPaperServerURL BETA: got '$got' want '$want'"
+  fi
+)
+
+# getPaperServerChecksum returns the SHA256 for the STABLE channel
+(
+  getServerVersion() { printf "1.21.4"; }
+  > "$propfile"
+  got=$(getPaperServerChecksum "$testworld")
+  want="stablechecksum456"
+  if [ "$got" != "$want" ]; then
+    terr "getPaperServerChecksum STABLE: got '$got' want '$want'"
+  fi
+)
+
+# getCurrentPaperVersion skips a version family that has no STABLE builds
+cat > "$PAPER_PROJECT_JSON" << 'EOF'
+{
+  "versions": {
+    "26.1": ["26.1.1"],
+    "1.21": ["1.21.11", "1.21.10"]
+  }
+}
+EOF
+cat > "$_paper_test_location/paper_builds_26.1.1.json" << 'EOF'
+[{"channel": "ALPHA", "downloads": {"server:default": {"url": "https://test.example.com/paper-26.1.1-1.jar", "checksums": {"sha256": "alphachecksum"}}}}]
+EOF
+cat > "$_paper_test_location/paper_builds_1.21.11.json" << 'EOF'
+[{"channel": "STABLE", "downloads": {"server:default": {"url": "https://test.example.com/paper-1.21.11-128.jar", "checksums": {"sha256": "stablechecksum"}}}}]
+EOF
+got=$(getCurrentPaperVersion "$testworld")
+want="1.21.11"
+if [ "$got" != "$want" ]; then
+  terr "getCurrentPaperVersion alpha-family: got '$got' want '$want'"
+fi
+
+# clean up
+> "$propfile"
+rm -rf "$_paper_test_location"
+PAPER_PROJECT_JSON="$_orig_paper_project_json"
+LOCATION="$_orig_location"
+VERSIONS_LOCATION="$_orig_versions_location"
diff --git a/tests/mscs-server-version.sh b/tests/mscs-server-version.sh
new file mode 100644
index 00000000..35be31ac
--- /dev/null
+++ b/tests/mscs-server-version.sh
@@ -0,0 +1,106 @@
+#!/bin/sh
+
+# start with clean propfile
+> "$propfile"
+
+# --- getServerJar ---
+
+# vanilla type (default): returns minecraft_server.VERSION.jar
+(
+  getServerCurrentVersion() { printf "1.21.4"; }
+  getServerVersion() { printf "1.21.4"; }
+  > "$propfile"
+  got=$(getServerJar "$testworld")
+  want="minecraft_server.1.21.4.jar"
+  if [ "$got" != "$want" ]; then
+    terr "getServerJar vanilla: got '$got' want '$want'"
+  fi
+)
+
+# papermc type: returns paper.VERSION.jar
+(
+  getServerCurrentVersion() { printf "1.21.4"; }
+  getServerVersion() { printf "1.21.4"; }
+  printf "mscs-server-type=papermc\n" > "$propfile"
+  got=$(getServerJar "$testworld")
+  want="paper.1.21.4.jar"
+  if [ "$got" != "$want" ]; then
+    terr "getServerJar papermc: got '$got' want '$want'"
+  fi
+)
+
+# explicit mscs-server-jar overrides the type-based default
+(
+  getServerCurrentVersion() { printf "1.21.4"; }
+  getServerVersion() { printf "1.21.4"; }
+  printf "mscs-server-jar=custom.jar\n" > "$propfile"
+  got=$(getServerJar "$testworld")
+  want="custom.jar"
+  if [ "$got" != "$want" ]; then
+    terr "getServerJar custom: got '$got' want '$want'"
+  fi
+)
+
+# --- getServerURL ---
+
+# explicit mscs-server-url is returned verbatim
+(
+  getServerCurrentVersion() { printf "1.21.4"; }
+  getServerVersion() { printf "1.21.4"; }
+  printf "mscs-server-url=https://example.com/server.jar\n" > "$propfile"
+  got=$(getServerURL "$testworld")
+  want="https://example.com/server.jar"
+  if [ "$got" != "$want" ]; then
+    terr "getServerURL explicit: got '$got' want '$want'"
+  fi
+)
+
+# papermc type with no URL delegates to getPaperServerURL
+(
+  getServerCurrentVersion() { printf "1.21.4"; }
+  getServerVersion() { printf "1.21.4"; }
+  getPaperServerURL() { printf "https://papermc.test/paper.jar"; }
+  printf "mscs-server-type=papermc\n" > "$propfile"
+  got=$(getServerURL "$testworld")
+  want="https://papermc.test/paper.jar"
+  if [ "$got" != "$want" ]; then
+    terr "getServerURL papermc fallback: got '$got' want '$want'"
+  fi
+)
+
+# vanilla type with no URL delegates to getMinecraftVersionDownloadURL
+(
+  getServerCurrentVersion() { printf "1.21.4"; }
+  getServerVersion() { printf "1.21.4"; }
+  getMinecraftVersionDownloadURL() { printf "https://mojang.test/server.jar"; }
+  > "$propfile"
+  got=$(getServerURL "$testworld")
+  want="https://mojang.test/server.jar"
+  if [ "$got" != "$want" ]; then
+    terr "getServerURL vanilla fallback: got '$got' want '$want'"
+  fi
+)
+
+# --- getServerCommand ---
+
+# command contains the jar name, server location, and -jar flag
+(
+  getCurrentMinecraftVersion() { printf "1.21.4"; }
+  getServerVersion() { printf "1.21.4"; }
+  getServerJar() { printf "minecraft_server.1.21.4.jar"; }
+  getServerLocation() { printf "/opt/mscs/server"; }
+  > "$propfile"
+  got=$(getServerCommand "$testworld")
+  if ! printf "%s" "$got" | grep -qs "minecraft_server.1.21.4.jar"; then
+    terr "getServerCommand missing jar in: $got"
+  fi
+  if ! printf "%s" "$got" | grep -qs "/opt/mscs/server"; then
+    terr "getServerCommand missing location in: $got"
+  fi
+  if ! printf "%s" "$got" | grep -qs -- "-jar"; then
+    terr "getServerCommand missing -jar flag in: $got"
+  fi
+)
+
+# clean up
+> "$propfile"
diff --git a/tests/mscs-vanilla-version.sh b/tests/mscs-vanilla-version.sh
new file mode 100644
index 00000000..110dea50
--- /dev/null
+++ b/tests/mscs-vanilla-version.sh
@@ -0,0 +1,109 @@
+#!/bin/sh
+
+_vanilla_test_location=/tmp/mscs-vanillatest
+_orig_versions_json="$VERSIONS_JSON"
+VERSIONS_JSON="$_vanilla_test_location/version_manifest.json"
+mkdir -p "$_vanilla_test_location"
+
+cat > "$VERSIONS_JSON" << 'EOF'
+{
+  "latest": {"release": "1.21.4", "snapshot": "25w14a"},
+  "versions": [
+    {"id": "1.21.4", "releaseTime": "2024-12-03T10:00:00+00:00", "url": "https://example.com/1.21.4.json"},
+    {"id": "25w14a", "releaseTime": "2025-04-02T10:00:00+00:00", "url": "https://example.com/25w14a.json"},
+    {"id": "1.21.1", "releaseTime": "2024-08-08T10:00:00+00:00", "url": "https://example.com/1.21.1.json"}
+  ]
+}
+EOF
+
+# --- getCurrentMinecraftVersion ---
+
+# returns the latest release version by default
+: > "$propfile"
+got=$(getCurrentMinecraftVersion "$testworld")
+if [ "$got" != "1.21.4" ]; then
+  terr "getCurrentMinecraftVersion release: got '$got' want '1.21.4'"
+fi
+
+# returns snapshot version when mscs-version-type=snapshot
+printf "mscs-version-type=snapshot\n" > "$propfile"
+got=$(getCurrentMinecraftVersion "$testworld")
+if [ "$got" != "25w14a" ]; then
+  terr "getCurrentMinecraftVersion snapshot: got '$got' want '25w14a'"
+fi
+
+# --- getMinecraftVersionReleaseTime ---
+
+got=$(getMinecraftVersionReleaseTime "1.21.4")
+if [ "$got" != "2024-12-03T10:00:00+00:00" ]; then
+  terr "getMinecraftVersionReleaseTime 1.21.4: got '$got' want '2024-12-03T10:00:00+00:00'"
+fi
+
+got=$(getMinecraftVersionReleaseTime "1.21.1")
+if [ "$got" != "2024-08-08T10:00:00+00:00" ]; then
+  terr "getMinecraftVersionReleaseTime 1.21.1: got '$got' want '2024-08-08T10:00:00+00:00'"
+fi
+
+# --- getClientVersion ---
+
+# returns current version by default when mscs-client-version is not set
+(
+  getCurrentMinecraftVersion() { printf "1.21.4"; }
+  : > "$propfile"
+  got=$(getClientVersion "$testworld")
+  if [ "$got" != "1.21.4" ]; then
+    terr "getClientVersion default: got '$got' want '1.21.4'"
+  fi
+)
+
+# returns pinned version when mscs-client-version is set in propfile
+(
+  getCurrentMinecraftVersion() { printf "1.21.4"; }
+  printf "mscs-client-version=1.20.4\n" > "$propfile"
+  got=$(getClientVersion "$testworld")
+  if [ "$got" != "1.20.4" ]; then
+    terr "getClientVersion pinned: got '$got' want '1.20.4'"
+  fi
+)
+
+# --- getClientJar ---
+
+# returns VERSION.jar by default
+(
+  getCurrentMinecraftVersion() { printf "1.21.4"; }
+  getClientVersion() { printf "1.21.4"; }
+  : > "$propfile"
+  got=$(getClientJar "$testworld")
+  if [ "$got" != "1.21.4.jar" ]; then
+    terr "getClientJar default: got '$got' want '1.21.4.jar'"
+  fi
+)
+
+# returns custom jar when mscs-client-jar is configured
+(
+  getCurrentMinecraftVersion() { printf "1.21.4"; }
+  getClientVersion() { printf "1.21.4"; }
+  printf "mscs-client-jar=custom-client.jar\n" > "$propfile"
+  got=$(getClientJar "$testworld")
+  if [ "$got" != "custom-client.jar" ]; then
+    terr "getClientJar custom: got '$got' want 'custom-client.jar'"
+  fi
+)
+
+# --- getClientLocation ---
+
+# returns path with version substituted (DEFAULT_CLIENT_LOCATION = $HOME/.minecraft/versions/$CLIENT_VERSION)
+(
+  getCurrentMinecraftVersion() { printf "1.21.4"; }
+  getClientVersion() { printf "1.21.4"; }
+  : > "$propfile"
+  got=$(getClientLocation "$testworld")
+  if ! printf "%s" "$got" | grep -qs "1.21.4"; then
+    terr "getClientLocation default: '1.21.4' not found in '$got'"
+  fi
+)
+
+# clean up
+: > "$propfile"
+rm -rf "$_vanilla_test_location"
+VERSIONS_JSON="$_orig_versions_json"
diff --git a/tests/mscs-world-lifecycle.sh b/tests/mscs-world-lifecycle.sh
new file mode 100644
index 00000000..75967184
--- /dev/null
+++ b/tests/mscs-world-lifecycle.sh
@@ -0,0 +1,83 @@
+#!/bin/sh
+
+# Use an isolated directory so getEnabledWorlds/getDisabledWorlds only see our
+# test worlds, not every directory in /tmp.
+_orig_worlds_location="$WORLDS_LOCATION"
+WORLDS_LOCATION=/tmp/mscs-lifecycletest
+rm -rf "$WORLDS_LOCATION"
+mkdir -p "$WORLDS_LOCATION"
+
+_lc_world="lc-testworld"
+_sprops="$WORLDS_LOCATION/$_lc_world/server.properties"
+_mprops="$WORLDS_LOCATION/$_lc_world/mscs.properties"
+
+# createWorld creates the world directory
+createWorld "$_lc_world" 25565 ""
+if [ ! -d "$WORLDS_LOCATION/$_lc_world" ]; then
+  terr "createWorld: world directory not created"
+fi
+
+# createWorld writes correct values to server.properties
+for _kv in "server-port=25565" "enable-query=true" "query.port=25565" "level-name=$_lc_world"; do
+  if ! grep -qs "^$_kv" "$_sprops"; then
+    terr "createWorld: server.properties missing '$_kv'"
+  fi
+done
+
+# createWorld enables the world in mscs.properties
+if ! grep -qs "^mscs-enabled=true" "$_mprops"; then
+  terr "createWorld: mscs.properties missing mscs-enabled=true"
+fi
+
+# getEnabledWorlds includes the new world
+_worlds=$(getEnabledWorlds)
+if ! listContains "$_lc_world" "$_worlds"; then
+  terr "getEnabledWorlds: expected '$_lc_world' in '$_worlds'"
+fi
+
+# isWorldEnabled returns success for an enabled world
+if ! isWorldEnabled "$_lc_world"; then
+  terr "isWorldEnabled: expected true for '$_lc_world'"
+fi
+
+# disableWorld sets mscs-enabled=false
+disableWorld "$_lc_world"
+if ! grep -qs "^mscs-enabled=false" "$_mprops"; then
+  terr "disableWorld: mscs.properties missing mscs-enabled=false"
+fi
+
+# isWorldEnabled returns failure after disableWorld
+if isWorldEnabled "$_lc_world"; then
+  terr "isWorldEnabled: expected false after disableWorld"
+fi
+
+# isWorldDisabled returns success after disableWorld
+if ! isWorldDisabled "$_lc_world"; then
+  terr "isWorldDisabled: expected true after disableWorld"
+fi
+
+# getDisabledWorlds includes the world; getEnabledWorlds does not
+_disabled=$(getDisabledWorlds)
+_enabled=$(getEnabledWorlds)
+if ! listContains "$_lc_world" "$_disabled"; then
+  terr "getDisabledWorlds: expected '$_lc_world' in '$_disabled'"
+fi
+if listContains "$_lc_world" "$_enabled"; then
+  terr "getEnabledWorlds: expected '$_lc_world' absent from '$_enabled'"
+fi
+
+# enableWorld restores the world to enabled
+enableWorld "$_lc_world"
+if ! isWorldEnabled "$_lc_world"; then
+  terr "isWorldEnabled: expected true after enableWorld"
+fi
+
+# deleteWorld removes the world directory
+deleteWorld "$_lc_world"
+if [ -d "$WORLDS_LOCATION/$_lc_world" ]; then
+  terr "deleteWorld: world directory still exists"
+fi
+
+# clean up
+rm -rf "$WORLDS_LOCATION"
+WORLDS_LOCATION="$_orig_worlds_location"
diff --git a/update.d/20-versions-subfolder b/update.d/20-versions-subfolder
new file mode 100644
index 00000000..c7465e7f
--- /dev/null
+++ b/update.d/20-versions-subfolder
@@ -0,0 +1,15 @@
+#!/bin/sh
+LOCATION=$(grep -m1 '^mscs-location=' /opt/mscs/mscs.defaults 2>/dev/null | cut -d= -f2)
+LOCATION=${LOCATION:-/opt/mscs}
+OLD="$LOCATION/version_manifest.json"
+NEW_DIR="$LOCATION/versions"
+NEW="$NEW_DIR/version_manifest.json"
+if [ -s "$OLD" ] && [ ! -s "$NEW" ]; then
+  printf "Migrating version_manifest.json to versions subfolder.\n"
+  mkdir -p "$NEW_DIR"
+  mv "$OLD" "$NEW"
+fi
+if [ -s "$OLD.bak" ] && [ ! -s "$NEW.bak" ]; then
+  mkdir -p "$NEW_DIR"
+  mv "$OLD.bak" "$NEW.bak"
+fi