Sir, You Are Being Hunted is a 2013 classic sandbox stealth experience from Big Robot Ltd. They've teamed up with Den Of Thieves Games to bring a huge overhaul to the game and a new Sir, You Are Being Hunted: Reinvented Edition has been announced for 2022.
The Reinvented Edition is actually being made for the Nintendo Switch as a "comprehensive remaster" but it's also coming as a standalone game for Linux, macOS and Windows in 2022 with "enhanced visuals, new gameplay options, a modern engine, bigger islands, faster procedural generation, and more".
When it comes to the update to the original game though, it's a big one. A huge bump in the version of the Unity game engine used with Unity 2021.1.18f1 (was Unity 4.6.1f1), online multiplayer was restored, graphical improvements like a new water shader, better distance rendering, a bunch of new high-end graphics options were added, HUD improvements for different resolutions, performance improvements and the list goes on.
Sir is probably one of the most unique stealth games around. Hard too but it's supposed to be, with a brutal AI that will keep you running and hiding for hours.