The details for the System Override event can be found here, including what new cosmetics you can unlock when you start racking up those Heirloom Shards.

Here are the patch notes, straight from EA:

Apex Legends System Override Collection Patch Notes

Bloodhound

Increased the scan distance for Eye of the Allfather by 3x. Increased time to activate: . 4s -> . 8sIncreased duration of scan: 2s -> 3s

Gibraltr

Gun Shield health reduced: 75 -> 50.

Crypto

Primary weapons will now automatically reload while in drone view.

Inventory Update

Base inventory slots increased 8 -> 10. Common Backpack: expands inventory to 12 slots. Rare Backpack: expands inventory to 14 slots. Epic Backpack: expands inventory to 16 slots. Grenade stacks reduced to 2 -> 1. Light / Heavy / Energy ammo stacks reduced from 80 -> 60. Syringe and Shield Cell stacks reduced from 6 -> 4. Med Kit and Shield Battery stacks reduced from 3 -> 2.

Peacekeeper

Mag size reduced from 6 -> 5. Increased reload time from 2. 5s -> 2. 65s. Increased reload time with empty mag from 3. 5s -> 3. 6s. Slightly increased the scale of the blast pattern from 1. 6 -> 1. 7.

Sentinel

Base damage increased from 65 -> 70Reduced time it takes to rechamber from 1. 85s -> 1. 75s.

Quality of Life

Muzzle flash adjustments:Reduced the intensity of muzzle flash while aiming down the sight for all weapons except shotties and snipersRed dot has been added to the iron sights for Prowler and L-STAR; iron sights dot will stay properly centered during weapon sway and bob movements. Heirloom crafting- Heirloom shards will now drop that can be used to purchase Heirlooms.

This patch might not be massive but it will heavily impact the meta. The Bloodhound and Gibraltr limit their tactical viability, making it more difficult for them to engage in a team fight. The changes to how the inventory system will give players some relief when trying to build up their arsenal. Now, they have a little more wiggle room to decide what to hold on to during their matches.

Not a fan of the Peacekeeper nerfs but Sentinel should now be a more practical gun.

These balance changes continue to make Apex Legends stand out from the competition, constantly updating the game so it stays fresh and unique.