High Volume SMS Stopped Working

After updating to the newest SDK, our High Volume SMS PHP app stopped working. The only change I could see for our code was changing the URL from /batch to /batches. The error that I get is `400 Bad Request` response: {"errorCode":"CMN-101","message":"Parameter [from] value is invalid.". I also tried a test file copying the new version's sample code and copied all the credentials from the control panel. That also has the same error. Wondering if something got messed up in our account settings. The login requests work fine. Our client ID is J6Vf4T1PRGeFpKip9qm-nw.

The array being sent to the post function is:

Array
(
[from] => +1xxx3668245
[text] => test
[messages] => Array
(
[0] => Array
(
[to] => Array
(
[0] => +1206353xxxx
)
)


[1] => Array
(
[to] => Array
(
[0] => +1425xxxxxxxx
)
)


[2] => Array
(
[to] => Array
(
[0] => +1425744xxxx
)
)


[3] => Array
(
[to] => Array
(
[0] => +1425xxxxxxxx
)
)
)
)