This post describes how to access migrated mobile web payment page.
First, do usual product booking using mobile web, until you reach payment page. You will have this kind of URL in your browser (assumed that you are doing testing in production, but it would also be the same if you test it in shared staging machine):
https://m.traveloka.com/en/payment/select/1568723580951219459/c9726b2c6c
Second, click your browser address bar, replace the word select in URL written there to selection. It should be changed to the following URL:
https://m.traveloka.com/en/payment/selection/1568723580951219459/c9726b2c6c
Third, press enter. The page now should use Commerce API v2.
p.s.
Please ping @imam for unclear instructions, or if you have any problems to access it.