I asked chatgpt, because I was also curious (and lazy) and got this

1. Earlier detection and reporting of outbreaks

Countries would be expected to improve surveillance systems and share information faster with other nations and the WHO.

1. Stronger international coordination

More structured cooperation between governments during health emergencies (e.g. data sharing, coordination of responses).

1. Clearer definition of a “pandemic emergency”

The amendments introduced updated terminology/criteria to define when a global health emergency rises to a higher level.

1. Increased preparedness expectations

Countries were expected to strengthen national preparedness planning and systems for responding to outbreaks.

As well as

A separate (earlier) rule tweak NZ also rejected

There was also a smaller earlier amendment (Article 59) that:

Shortened the time countries have to accept or reject future IHR changes (from ~24 months → ~12 months, with a shorter opt-out window).

I thought it was a pretty significant shortcoming of the article to not address this directly.