Why does WhatsApp work on the old number when changing the SIM card - briefly?
WhatsApp continues to function with the old number even after a SIM card change because it is linked to the phone number, not the SIM card. The app uses your phone's internet connection instead of relying on the cellular network provided by the SIM card.
Why does WhatsApp work on the old number when changing the SIM card - in detail?
When a user changes their SIM card, WhatsApp continues to function using the old phone number due to several key factors. Firstly, WhatsApp does not rely solely on the SIM card for operation; instead, it uses an internet connection to send and receive messages. The SIM card is primarily used during the initial setup of the app to verify the phone number associated with the account. Once this verification process is complete, WhatsApp can function independently of the physical SIM card.
Moreover, WhatsApp utilizes a unique identifier called the "WhatsApp ID" that is tied to the user's phone number rather than the SIM card itself. This ID allows the app to maintain continuity across different devices and networks. When a new SIM card is inserted into the device, WhatsApp does not require re-verification as long as the phone number remains the same.
Additionally, WhatsApp employs end-to-end encryption for all communications, which ensures that messages are securely sent and received regardless of changes in the SIM card. This encryption mechanism operates independently of the SIM card, further enabling seamless functionality even after a SIM change.
In summary, WhatsApp's ability to work with the old phone number when changing the SIM card is facilitated by its reliance on internet connectivity, use of a unique WhatsApp ID tied to the phone number, and end-to-end encryption for secure messaging. These factors collectively ensure that users can continue using WhatsApp without interruption, even after switching SIM cards.