ChatApp has implemented its own algorithm for converting Argentinean phone numbers into suitable numbers for use in WhatsApp.

When dealing with Argentine telephone numbers (with the country code "54"), it's crucial to follow this specific format: insert the digit 9 between the country code and the area code, while eliminating the code "15" at the beginning. This format results in a 13-digit phone number: +54 9 XXX XXX XXX XXXX.

• For outgoing messages to Argentine numbers, simply insert the digit 9 immediately after 54. For example: 541136198377 becomes 5491136198377.
• For incoming messages, we apply the reverse operation. For instance: 5491136198377 reverts back to 541136198377.