It appears that the LTE versions of the Lumia 640 and Lumia 640 XL in Latin America have a small firmware update available. The update, which seems at the moment to be regional, bumps the firmware of both phones to 02177.00000.16025.27003.

From (translated from Spanish):

The Lumia 640 LTE and Lumia 640 XL LTE who are receiving the update have the main features that have ROM Country Variant found in Update 2 for Windows Phone 8.1, which would be logical because they do not depend on operators for separate updates. This update modifies the firmware of the devices that receive it, putting in version 02177.00000.16025.27003 jumping from the 02177.00000.15184.36002, last documented on the official website of Microsoft on updates .

It's not clear at this time what, if any, changes this update brings. We'll be sure to keep you posted on any developments.