@movq@www.uninformativ.de Thanks for the catch-up. I live in that state, so I experienced firsthand the change.

Basically, our state had an ICANN region (Mexican Mountain Time/MT), but the government said “Forget that and follow Mexican Central Time”.
But as the state on the border, Texas, USA, stays with American MT, that made some trouble between companies and offices.
That has happened before, the municipalities/regions had different start and end for DST for 1 or 2 weeks, but now they have 1 hr offset all the year.

Municipalities affected in this State

tl;dr ICANN timezone America/Chihuahua is not gonna be used anymore. Some municipalities are going to switch to America/Mexico_City and some others to US/Mountain. In the future, when USA removes DST, those states are going to follow. Regions on the border will follow American regulations. #sovereigntyFTW