Postinstall script isn't working with new 230.4.8797 app version.

I’ve been deploying Dropbox via a custom postinstall script to extract the HelperTools without prompting for admin credentials. This approach has worked for previous versions.

With the current version, however, I now see an admin prompt after installation. If I decline, Dropbox shows the badge:

"Dropbox is not updating automatically. Enable automatic updates so the app works smoothly." (translated from german)

Here’s the relevant part of my postinstall script:

#!/bin/sh
HELPER_SRC_PATH=/Applications/Dropbox.app/Contents/Resources/DropboxHelperInstaller.tgz
HELPER_DST_DIR=/Library/DropboxHelperTools
HELPER_DST_PATH="$HELPER_DST_DIR/DropboxHelperInstaller"

if [ -e "$HELPER_SRC_PATH" ]; then
  [ -d "$HELPER_DST_DIR" ] || mkdir "$HELPER_DST_DIR"
  /usr/bin/tar -C "$HELPER_DST_DIR" -xz -f "$HELPER_SRC_PATH"
  /usr/sbin/chown root:wheel "$HELPER_DST_PATH" "$HELPER_DST_DIR"
  /bin/chmod 04511 "$HELPER_DST_PATH"
else
  echo "Expected $HELPER_SRC_PATH, but it was not present."
  exit 1
fi

This script worked in previous versions, always extracting the helper tool silently. I would like to understand:

Has the HelperTool installation process changed in this Dropbox version?
Is there a supported way to deploy Dropbox without triggering the admin prompt while still allowing automatic updates?

Thanks in advance for your guidance.