Effective 2019.08.03, the Federal Telecommunications Institute of Mexo are introducing changes to their numbering plan.
Mexico (country code 52) has traditionally prefixed mobile numbers with a 1 before the subscriber number internationally - so a number starting with 521 was easily identifyable as a mobile number. From August 3rd onwards that one should be omitted.
For example a number published locally as 045 56 1234 5678 would be dialed as :
011 52 1 56 1234 5678 prior to August 3rd.
011 52 56 1234 5678 on or after August 3rd.
Please update your staff as required regarding the changes - while we do not expect any trouble during transition, please report any issues you have to your support contact.
Thank you,
BitBlock Systems, Inc.