My idea for update.

In the upper yard there'd be a new cold biome called the Fridge, there would be new types of food (sth. like frozen food etc.) and lots of Ice Cap Mints. Entering the Fridge will give you freezing effect (something similar to burning effect on Sandbox or BBQ spill), but it would additionally slow you down. Using 'spicy safety' mutation will slow down the freezing effect and weaken the slow that this effect gives you. There would also be randomly spawned new material called 'dog fur' which would be only able to gather with tier 3 axe. It would be used to craft new dog fur armor which would give you 'freezing protection' effect (which makes you freeze slower- something similar to antlion armor). There would be also some new bugs such as new beetles, ticks, bumblebees and maybe a grasshopper mini boss. There would be a way to turn off the fridge (like the haze biome) by unpluging the cable from the fridge (using a tool crafted from the Fridge biome bugs).