Technical: weapon effects are moving to a new system.
Hundreds of weapons have custom-coded effects, like healing a fast pet or cursing on a lucky hit. Until now, each one was its own small program, written by hand and run in the middle of your battle. We've rebuilt those effects as rules the battle reads: when this is true, do that. Weapons will switch over in batches over the next few weeks, and every weapon should work exactly as before. If one acts differently after it switches, please report it with the weapon's name and what happened.

One exception: Malerias Clawed Glove.
Its curse used to reach outside the battle. About a quarter of the time, it set up to 15 of your other pets to 0 HP, or dropped their hunger or happiness to 1. Once the glove switches over, you'll still see the curse message, but your other pets are left alone.

Why it matters: more new weapons.
Adding a weapon with a special effect used to mean writing and testing new code from scratch, which is a big part of why so few new weapons have come out. Most "recent" weapons have needed some custom code to stay fresh or to balance between tiers. Now staff can build effects in the weapon editor from shared pieces and combine them in ways the old code never managed. That leaves room for a lot more weapons, and stranger ones.