diff --git a/scripts/dotdrop-version-manager.sh b/scripts/dotdrop-version-manager.sh
index e1b8af0..574c0f0 100755
--- a/scripts/dotdrop-version-manager.sh
+++ b/scripts/dotdrop-version-manager.sh
@@ -5,15 +5,32 @@
 api="https://api.github.com/repos"
 pro="deadc0de6/dotdrop"
 
+git_get_changes()
+{
+  #git fetch origin
+  git remote update
+}
+
 # get current status
 get_current()
 {
-  tag=`git describe --tags 2>/dev/null`
-  branch=`git branch --show-current 2>/dev/null`
+  tag=$(get_current_tag)
   [ "$tag" != "" ] && echo "tag: ${tag}"
+  branch=$(get_current_branch)
   [ "$branch" != "" ] && echo "branch: ${branch}"
 }
 
+# get current tag
+get_current_tag()
+{
+  git describe --tags 2>/dev/null
+}
+
+get_current_branch()
+{
+  git branch --show-current 2>/dev/null
+}
+
 # get latest release
 get_latest()
 {
@@ -32,25 +49,90 @@ get_branches()
   curl "${api}/${pro}/branches" 2>/dev/null | grep name | sed 's/^.*: "\(.*\)",/\1/g'
 }
 
+need_update()
+{
+  git fetch origin >/dev/null 2>&1
+  cur=$(get_current_tag)
+  if [ "${cur}" != "" ]; then
+    last=$(get_latest)
+    [ "${last}" != "${cur}" ] && echo "new version available: ${last}" && return
+  fi
+  changes=$(git status -s)
+  [ "${changes}" != "" ] && echo "new updates available" && return
+  echo "your version is up-to-date"
+}
+
+checkout_last_tag()
+{
+  last=$(get_latest)
+  [ "${last}" = "" ] && echo "unable to get last release" && return
+  cur=$(get_current_tag)
+  [ "${cur}" = "${last}" ] && return
+  git_get_changes && git checkout "${last}"
+}
+
+# $1: tag
+checkout_tag()
+{
+  cur=$(get_current_tag)
+  [ "${cur}" = "${1}" ] && return
+  git_get_changes && git checkout "${1}"
+}
+
+checkout_branch()
+{
+  git_get_changes && git checkout "${1}" && git pull origin "${1}"
+}
+
+# move to base of dotdrop
+move_to_base()
+{
+  curpwd=$(pwd)
+  git submodule | grep dotdrop >/dev/null 2>&1
+  if [ "$?" ]; then
+    # dotdrop is a submodule
+    echo "dotdrop used as a submodule"
+    cd dotdrop || echo "cannot change directory to dotdrop" && exit 1
+    return
+  fi
+
+  if [ -e dotdrop/version.py ]; then
+    grep deadc0de6 dotdrop/version.py >/dev/null 2>&1
+    if [ "$?" ]; then
+      # dotdrop is in current dir
+      echo "dotdrop is in current directory"
+      return
+    fi
+  fi
+
+  echo "dotdrop wasn't found"
+  exit 1
+}
+
 # print usage
 usage()
 {
-  echo "${0} current:              current version tracked"
-  echo "${0} releases:             list all releases"
-  echo "${0} branches:             list all branches"
-  echo "${0} get latest:           get latest stable release"
-  echo "${0} get master:           get master branch"
-  echo "${0} get <version>:        get a specific version"
-  echo "${0} get branch <branch>:  get a specific version"
+  echo "$(basename "${0}") current              : current version tracked"
+  echo "$(basename "${0}") releases             : list all releases"
+  echo "$(basename "${0}") branches             : list all branches"
+  echo "$(basename "${0}") check                : check for updates"
+  echo "$(basename "${0}") get latest           : get latest stable release"
+  echo "$(basename "${0}") get master           : get master branch"
+  echo "$(basename "${0}") get <version>        : get a specific version"
+  echo "$(basename "${0}") get branch <branch>  : get a specific version"
 }
 
 [ "$1" = "" ] && usage && exit 1
-[ "$1" != "current" ] && [ "$1" != "releases" ] && [ "$1" != "get" ] && [ "$1" != "branches" ] && usage && exit 1
+[ "$1" != "current" ] && \
+  [ "$1" != "releases" ] && \
+  [ "$1" != "get" ] && \
+  [ "$1" != "branches" ] && \
+  [ "$1" != "check" ] && \
+  usage && exit 1
 [ "$1" = "get" ] && [ "$2" = "" ] && usage && exit 1
 [ "$1" = "get" ] && [ "$2" = "branch" ] && [ "$3" = "" ] && usage && exit 1
 
-curpwd=`pwd`
-cd dotdrop
+move_to_base
 
 if [ "$1" = "current" ]; then
   get_current
@@ -58,25 +140,20 @@ elif [ "$1" = "releases" ]; then
   get_releases
 elif [ "$1" = "branches" ]; then
   get_branches
+elif [ "$1" = "check" ]; then
+  need_update
 elif [ "$1" = "get" ]; then
   if [ "$2" = "latest" ]; then
-    last=$(get_latest)
-    git fetch origin
-    git checkout ${last}
+    checkout_last_tag
   elif [ "$2" = "master" ]; then
-    git fetch origin
-    git checkout master
-    git pull
+    checkout_branch master
   elif [ "$2" = "branch" ]; then
-    git fetch origin
-    git checkout ${3}
-    git pull origin ${3}
+    checkout_branch "${3}"
   else
-    git fetch origin
-    git checkout ${2}
+    checkout_tag "${2}"
   fi
 fi
 
-cd ${curpwd}
+cd "${curpwd}" || true
 
 exit 0