What's the status of off-chain smart contracts?

I’m looking to develop an application on Algorand that requires managing tokens with some degree of privacy. I believe an off-chain contract would be the appropriate way to setup this application’s architecture.

I’ve looked for resources on Getting Started with off-chain contracts but sadly couldn’t find anything.
The most relevant piece of documentation I’ve encountered is Silivio’s Algorand Smart Contract Architecture blog post.

What’s the current status of off-chain smart contracts on Algorand? Is there any documentation / discussion you could point me towards?