Visitor visa extension - I-134 required?

[Cacofonix]

Is it necessary to provide I-134 and documentation associated with I-134 (statement from bank office, employer, etc.) along with the extension application? The reason I ask is that I-539 instructions only require reason for extension, proof that the extended stay would be temporary, and the effect the extension would have on employment or residency. It doesn't specifically ask to provide another affidavit of support. Since I already provided one when they applied for the original visa and they are in the US under that visa, wouldn't that already govern their stay and my obligations?

Curious as to what folks who have extended their parent's visitor B-2 visa have done. Appreciate your thoughts.

[immihelp]

Yes, I-134 and other supporting documents are required.

Read https://www.immihelp.com/visitors-visa-extension/