I was under the impression that TCP/IP v.6 being used by Thai internet providers was a distant dream. However, I just did a ping test and got:

Microsoft Windows [Version 10.0.10586]
(c) 2015 Microsoft Corporation. All rights reserved.
 
C:\>ping yahoo.com
 
Pinging yahoo.com [2001:4998:44:204::a7] with 32 bytes of data:
Reply from 2001:4998:44:204::a7: time=389ms
Reply from 2001:4998:44:204::a7: time=389ms
Reply from 2001:4998:44:204::a7: time=391ms
Reply from 2001:4998:44:204::a7: time=388ms
 
Ping statistics for 2001:4998:44:204::a7:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 388ms, Maximum = 391ms, Average = 389ms

In the past the "yahoo.com" always resolved to a TCP/IP v.4 address. Is this new?

FWIW, I'm using a True DOCSIS 30/3 plan.

No idea as I still get the v4 address (WiNet router doesn't support 6)

Pinging yahoo.com [206.190.36.45] with 32 bytes of data:
Reply from 206.190.36.45: bytes=32 time=260ms TTL=43
Reply from 206.190.36.45: bytes=32 time=259ms TTL=43
Reply from 206.190.36.45: bytes=32 time=257ms TTL=43
Reply from 206.190.36.45: bytes=32 time=260ms TTL=43

Ping statistics for 206.190.36.45:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 257ms, Maximum = 260ms, Average = 259ms

I am on 10Mb TOT WiNet (Wireless)

Not sure if this is a random coincidence or a connected event, but my True modem/router just spontaneously rebooted. I was reading forum posts and suddenly had no connection. I looked at the modem/router and all the appropriate lights were blinking like it was rebooting.

Pinging yahoo.com now resolves to v.4 address like MJCM shows above.

Hmmmm.

^Maybe just a brief test and you were lucky you noticed it ?

Kinda like an uninvited beta tester?