diff --git a/bin/rename-env-vars-5-0 b/bin/rename-env-vars-5-0
new file mode 100755
index 0000000..38ecb34
--- /dev/null
+++ b/bin/rename-env-vars-5-0
@@ -0,0 +1,44 @@
+#! /usr/bin/env bash
+# shellcheck source-path=..
+
+set -euo pipefail
+
+#### Detect Toolkit Project Root ####
+# if realpath is not available, create a semi-equivalent function
+command -v realpath >/dev/null 2>&1 || realpath() {
+  [[ $1 = /* ]] && echo "$1" || echo "$PWD/${1#./}"
+}
+SCRIPT_PATH="$(realpath "${BASH_SOURCE[0]}")"
+SCRIPT_DIR="$(dirname "$SCRIPT_PATH")"
+TOOLKIT_ROOT="$(realpath "$SCRIPT_DIR/..")"
+if [[ ! -d "$TOOLKIT_ROOT/bin" ]] || [[ ! -d "$TOOLKIT_ROOT/config" ]]; then
+  echo "ERROR: could not find root of overleaf-toolkit project (inferred project root as '$TOOLKIT_ROOT')"
+  exit 1
+fi
+
+source "$TOOLKIT_ROOT/lib/shared-functions.sh"
+
+function usage() {
+  echo "Usage: bin/update-env"
+  echo ""
+  echo "Updates config/variables.env, adding new environment variables"
+  echo ""
+}
+
+function __main__() {
+  if [[ "${1:-null}" == "help" ]] || [[ "${1:-null}" == "--help" ]]; then
+    usage
+    exit
+  fi
+
+  # read_image_version
+  echo "This script will update your config/variables.env."
+  echo "We recommend backing up your config with bin/backup-config."
+  prompt "Do you want to continue?"
+
+  rebrand_sharelatex_env_variables
+
+  echo "Done."
+}
+
+__main__ "$@"
diff --git a/bin/up b/bin/up
index 99317b8..35b583d 100755
--- a/bin/up
+++ b/bin/up
@@ -35,6 +35,22 @@ function check_config() {
   fi
 }
 
+function check_sharelatex_env_vars() {
+  local invalid_prefix="SHARELATEX_"
+  if [[ "$IMAGE_VERSION_MAJOR" -lt 5 ]]; then
+    invalid_prefix="OVERLEAF_"
+  fi
+
+  if grep -q "$invalid_prefix" "$TOOLKIT_ROOT/config/variables.env"; then
+    echo "WARNING: some environment variables defined in config/variables.env" 
+    echo "contain '$invalid_prefix' in their name"
+    echo "Starting with Overleaf CE and Server Pro 5.0.0 the environment variables" 
+    echo "use the prefix 'OVERLEAF_'  instead of 'SHARELATEX_'."
+    echo "Please check your config/version and config/variables.env files"
+    prompt "Do you want to continue?"
+  fi
+}
+
 function initiate_mongo_replica_set() {
   echo "Initiating Mongo replica set..."
   "$TOOLKIT_ROOT/bin/docker-compose" up -d mongo
@@ -52,9 +68,10 @@ function __main__() {
     exit
   fi
 
-  check_config
-  read_config
   read_image_version
+  check_config
+  check_sharelatex_env_vars
+  read_config
 
   if [[ "$MONGO_ENABLED" == "true" && "$IMAGE_VERSION_MAJOR" -ge 4 ]]; then
     initiate_mongo_replica_set
diff --git a/bin/upgrade b/bin/upgrade
index 1a7d9c6..5f0a645 100755
--- a/bin/upgrade
+++ b/bin/upgrade
@@ -15,6 +15,8 @@ if [[ ! -d "$TOOLKIT_ROOT/bin" ]] || [[ ! -d "$TOOLKIT_ROOT/config" ]]; then
   exit 1
 fi
 
+source "$TOOLKIT_ROOT/lib/shared-functions.sh"
+
 function usage() {
   echo "Usage: bin/upgrade"
   echo ""
@@ -87,22 +89,27 @@ function show_changes() {
   echo "----------"
 }
 
-function handle_image_upgrade() {
-  local user_image_version
-  user_image_version="$(head -n 1 "$TOOLKIT_ROOT/config/version")"
-  local seed_image_version
-  seed_image_version="$(head -n 1 "$TOOLKIT_ROOT/lib/config-seed/version")"
+function read_seed_image_version() {
+  SEED_IMAGE_VERSION="$(head -n 1 "$TOOLKIT_ROOT/lib/config-seed/version")"
+  if [[ ! "$SEED_IMAGE_VERSION" =~ ^([0-9]+)\.([0-9]+)\.[0-9]+(-RC[0-9]*)?(-with-texlive-full)?$ ]]; then
+    echo "ERROR: invalid config-seed/version '${SEED_IMAGE_VERSION}'"
+    exit 1
+  fi
+  SEED_IMAGE_VERSION_MAJOR=${BASH_REMATCH[1]}
+  SEED_IMAGE_VERSION_MINOR=${BASH_REMATCH[2]}
+}
 
-  if [[ ! "$seed_image_version" > "$user_image_version" ]]; then
+function handle_image_upgrade() {
+  if [[ ! "$SEED_IMAGE_VERSION" > "$IMAGE_VERSION" ]]; then
     echo "No change to docker image version"
     return 0
   fi
 
-  echo "New docker image version available ($seed_image_version)"
-  echo "Current image version is '$user_image_version' (from config/version)"
+  echo "New docker image version available ($SEED_IMAGE_VERSION)"
+  echo "Current image version is '$IMAGE_VERSION' (from config/version)"
 
-  local user_image_major_version="$(echo "$user_image_version" | awk -F. '{print $1}')"
-  local seed_image_major_version="$(echo "$seed_image_version" | awk -F. '{print $1}')"
+  local user_image_major_version="$(echo "$IMAGE_VERSION" | awk -F. '{print $1}')"
+  local seed_image_major_version="$(echo "$SEED_IMAGE_VERSION" | awk -F. '{print $1}')"
   if [[ "$seed_image_major_version" > "$user_image_major_version" ]]; then
     echo "WARNING: this is a major version update, please check the Release Notes for breaking changes before proceeding:"
     echo "* https://github.com/overleaf/overleaf/wiki#release-notes"
@@ -112,11 +119,11 @@ function handle_image_upgrade() {
   read -r -p "Upgrade image? [y/n] " should_upgrade
 
   if [[ ! "$should_upgrade" =~ [Yy] ]]; then
-    echo "Keeping image version '$user_image_version'"
+    echo "Keeping image version '$IMAGE_VERSION'"
     return 0
   fi
 
-  echo "Upgrading config/version from $user_image_version to $seed_image_version"
+  echo "Upgrading config/version from $IMAGE_VERSION to $SEED_IMAGE_VERSION"
 
   ## Offer to stop docker services
   local services_stopped="false"
@@ -148,9 +155,15 @@ function handle_image_upgrade() {
   ## Set the new image version
   echo "Backing up old version file to config/__old-version"
   cp "$TOOLKIT_ROOT/config/version" "$TOOLKIT_ROOT/config/__old-version"
-  echo "Over-writing config/version with $seed_image_version"
+  echo "Over-writing config/version with $SEED_IMAGE_VERSION"
   cp "$TOOLKIT_ROOT/lib/config-seed/version" "$TOOLKIT_ROOT/config/version"
 
+  if [[ "$IMAGE_VERSION_MAJOR" -le 4 && "$SEED_IMAGE_VERSION_MAJOR" -ge 5 ]]; then 
+    echo "Renaming environment variables in config/variables.env"
+    prompt "Proceed with the environment variable renaming?"
+    rebrand_sharelatex_env_variables
+  fi
+
   ## Maybe offer to start services again
   if [[ "${services_stopped:-null}" == "true" ]]; then
     local should_start="n"
@@ -202,8 +215,13 @@ function __main__() {
     || [[ "${1:-null}" == "--help" ]] ; then
     usage && exit
   fi
+
   handle_git_update
+
+  read_seed_image_version
+  read_image_version
   handle_image_upgrade
+
   echo "Done"
   exit 0
 }
diff --git a/lib/shared-functions.sh b/lib/shared-functions.sh
index 825e458..8eb7e0b 100644
--- a/lib/shared-functions.sh
+++ b/lib/shared-functions.sh
@@ -17,3 +17,28 @@ function read_image_version() {
   IMAGE_VERSION_MAJOR=${BASH_REMATCH[1]}
   IMAGE_VERSION_MINOR=${BASH_REMATCH[2]}
 }
+
+prompt() {
+    read -p "$1 (y/n): " choice
+    if [[ ! "$choice" =~ [Yy] ]]; then
+        echo "Exiting."
+        exit 1
+    fi
+}
+
+rebrand_sharelatex_env_variables() {
+  set +o pipefail
+  sharelatex_occurrences=$(grep -o "SHARELATEX_" "$TOOLKIT_ROOT/config/variables.env" | wc -l | sed 's/ //g')
+  set -o pipefail
+  if [ "$sharelatex_occurrences" -gt 0 ]; then
+    echo "Found $sharelatex_occurrences lines with SHARELATEX_"
+    local timestamp=$(date "+%Y.%m.%d-%H.%M.%S")
+    echo "Creating backup file config/__old-variables.env.$timestamp"
+    cp config/variables.env config/__old-variables.env.$timestamp
+    echo "Replacing 'SHARELATEX_' with 'OVERLEAF_' in config/variables.env"
+    sed -i "s/SHARELATEX_/OVERLEAF_/g" "$TOOLKIT_ROOT/config/variables.env"
+    echo "Updated $sharelatex_occurrences lines in $TOOLKIT_ROOT/config/variables.env"
+  else
+    echo "No 'SHARELATEX_' ocurrences found in config/variables.env"
+  fi
+}