Can you not upgrade Perks in MP?

[July]

Looked it up and found some people from a few months ago saying you wouldn't be able to until the June 18th update only I still haven't found out how. Is it level locked? I'm a 32 now with Purple tier weapons and Characters yet all my perks are still Tier 1. Are upgraded perks exclusive to Characters while the Boss is locked to base tier?

[ThreadCutter]

You can, it's a new level up reward

[[YT] Ali.Chitax ✪]

you’ll earn level 2-3 cards by leveling up and choosing them as a reward

[Cyandos]

I wish we could choose categories to level up, or pay to get a re-roll or to choose a category

[July]

I guess since most of my progress was during the playtest, the Tier 2-3 upgrades weren't in the level up pool yet. Just got my first one at 38. This is gonna take a while.

[Flavio93Zena]

Tier 3 upgrades are not available at all.
Tier 2 upgrades are in the level up pool.

[Red Rum Lover]

I started getting tier 2 once i hit lvl 50.