Glad to hear you've enjoyed the game.
There has been no further development on this game since a few months after its release in 2017 (an update involving minor bug fixes and spelling/grammar improvements). For now all effort is being poured into the sequel, which is slated to be released this year. And this does feature a lot of improvements on the stealth gameplay aspects, including melee/non-lethal attacks for a full no-kill stealth approach.
Thank you for the kind comments and I hope you continue to enjoy the game.