I do not have access to the server environment and therefore cannot say with certainty whether there were security patches and whether these were installed on steemitdev.com.
However, as far as I can tell from the client code, it is not the version that is running on steemit.com.

You can see this from the latest commits:
✅ Changed TOS (Aug 2023)
...
✅ Changed GoogleAnalytics (Sep 2023)
❓Changed SCP (Sep 2023)
❌ Changed media rules (Dec 2023)

One could therefore assume that only the latest changes have not been adopted.