Item Evolution:
item evolution was released in the April 8th 2014 patch allowing certain items to be evolved, increasing their weight cap and stats but reverts them back to level 1. currently, only weapons have the ability to be evolved, however it has bee stated more items will be evolvable soon so maybe other items will be evolvable.
Buffs:
buffs that were already on the item will stay on the item when evolved.
Evolvable Items
murumasa katana ----> cursed murumasa
platinum knife ----> platinum blade
inferno ----> mega inferno
gorgeous palace key ----> heaven key
wand of the canary ----> Madame canary