To get this update, you have to opt in inside your library:
Necesse -> Properties -> Betas -> Select 0.20.x in dropdown.
It's recommended to back up your saves when playing on experimental version. Especially when loading a save using a newer version. You can do so in game on the load menu.

A quick reminder that there's an official Discord server, where you can post suggestions, bugs, or just talk with other players and the developer. Here's the invite link: https://discord.gg/FAFgrKD

This update adds items that expand on the summoner class with new weapons, trinkets and armor. Other than that there's a bunch of improvements like the ability to craft from nearby inventories in workstations, rendering optimizations, better version migration, sound direction rework and improved summoned mob AI.

Changelog

Additions:
Added random lava blob effects.
Added Summon Foci trinket.
Added Spider Staff summon weapon.
Added Mesmer Tablet trinket, found in dungeon chests.
Added Inducing Amulet trinket, found in pirate chests and item stands.
Added ability to craft using nearby inventories inside workstations. Can be disabled with new checkbox.

Changes/misc:
Optimized a bunch of rendering, mainly particles and projectiles by up to 4 times faster.
Expanded version migration system to allow for migration of items and mobs.
Changed smart mining toggle message to ON and OFF.
Reworked sound position/direction.
Summoned attacking mobs will no longer show their name on mouse hover.
Adjusted rock object top collision. Should prevent weird enemy path finding in caves.
Summoned mobs are no longer able to push around mobs that's mounted.
Updated Brain on a Stick item texture.
Changed a bunch of summon item IDs (shouldn't change anything with new migration system).
Summon items will now show max summons on the item, same as bow/gun ammo.
Buff duration text now has an outline to make it more readable.
Changed Spider armor set to be summon focused.
Tweaked follower AI, is now more responsive and doesn't chase targets out of sight and super far away.
Reapers Call will now do summon damage instead of magic.
Training dummies now show the total DPS for a player.
Increased range of player quickstack and restock.

Fixes:
Fixed wall torches sometimes rendering behind or in front of mobs when it shouldn't.
Fixed not being able to attack when mouse is over invisible tracking sidebar form.
Fixed crash relating to getting a time update from server.
Fixed various Void Wizard bugs introduced with new movement system.
Fixed gravel tile having wrong map color.

And a bunch of other smaller changes and fixes.
You might have to restart Steam to get the update.