I looked at your diff, it has a reference to https://en.wikipedia.org/wiki/Template:TMOblock which talks about T-Mobile IPv6 IPs. Yet the IP used on the edit is a T-Mobile IPv4 IP. Is it just that the wikipedia app forces IPv4 or something?

+1.. verifying it's me who made this report :)

In T234159#5532383, @Krenair wrote:

I looked at your diff, it has a reference to https://en.wikipedia.org/wiki/Template:TMOblock which talks about T-Mobile IPv6 IPs. Yet the IP used on the edit is a T-Mobile IPv4 IP. Is it just that the wikipedia app forces IPv4 or something?

probably.. If that's the case, WP app should always use whatever IP the device is using.

https://en.wikipedia.org/wiki/Wikipedia:Advice_to_T-Mobile_IPv6_users
When you access Wikipedia from a IPv6-compatible device on the T-Mobile network, a proxy server (with its own IPv6 address) retrieves and sends data to Wikipedia's servers on your behalf rather than your mobile device doing so directly.

I wonder what on earth T-Mobile USA is doing... Is this some attempt to give mobile devices IPv6 addressing without making it easy to track them? Hopefully this is something applied to all traffic going through their network and nothing dodgy is happening with Wikipedia traffic.
IAV/Apap04, can you confirm that editing while on this network from the browser shows an IPv6 address and editing from the android app shows an IPv4 address? Are these reflected when you go to a site like https://www.whatismyip.com/ ?

I had a quick search through the source of the android app and didn't notice anything obvious, could be in an upstream library though.

In the browser, I'm connected via an IPv6 address. Now, when I tested
editing in the app, I'm connected an IPv6 address that is blocked for
cross-wiki vandalism, not a regular TMOblock.

2607:fb90:64e8:663d:563d:f18d:ce4:9f27 is a T-Mobile IPv6 address. I don't see anything wrong here, other than lack of wikitext parsing...?

weird, because I was able to edit from an IPv4 address a couple minutes ago. I guess the browser and the app are using different IPs.

Maybe, but I don't think we've proven that yet. Did you check whatismyip.com and whether that matches any IP seen when you edited Wikipedia?

They match.

Okay so basically what we've seen then is from the browser you always edit from that IPv6 address, but from the app it will do either?

Yeah I guess so. Not sure what caused the switch to a different IP though.

Thanks for reporting this. Does the same behaviour happen if you try editing on the mobile website?

Nope. In the discussion with Krenair, it was suggested that the app uses
an IPv4 address and switches to IPv6 addresses. It's probably either the
app or T-Mobile.

Since we load pages in the same way as mobile web, it is almost certainly T-Mobile.