Earlier this year, software support for the Galaxy S10e, Galaxy S10, and Galaxy S10+ came to an end as the 2019 flagships finished four years on the market. These phones were eligible for three major OS upgrades and four years of security updates so they aren't supposed to get any new ones, but they're getting one anyway.
The Galaxy S10e, S10, and S10+ have received an update on the Telcel network in Mexico. The update brings with it a newer security patch (the September 2023 patch, to be exact) and comes with firmware version ending in HWI1.
It remains to be seen if other markets (and carriers) will get this update. It's possible it's just an exception for Galaxy S10s on Mexico's Telcel network, as the previous update for those S10s came out back in March when they were still eligible to receive security updates, so this is likely just the last hurrah from the carrier.
It's not meant to be taken as a sign that Samsung is extending support for security updates to match Google's crazy new policy that will see Pixel devices getting updates for at least seven years from launch. Even if Samsung revises its policy, which the company might actually end up doing, it will not be doing so for devices as old as the Galaxy S10.
In any case, Galaxy S10e, S10, and S10+ owners in Mexico can try downloading the update from their phone's Settings » Software update menu. An alternative method is to head to our archives, download the latest firmware for your phone and country, and install it using a Windows PC and a USB cable.