Telfonica/Movistar (71606) - the Sender ID on all messages will generally changed to a local number to ensure delivery
Nextel (71607) - generally sender is dynamic but some senders will be overwritten to ensure delivery
Claro (71610) is filtering alphanumeric and national numeric Sender ID. All SMS sent with those senderIDs will not be delivered. We suggest using numeric Sender ID with international number format to reduce the risk of being filtered.
There are no additional content restrictions beyond those in our Acceptable Use Policy
Other features/restrictions of note:
Handset delivery receipts are not supported.