Although it is somewhat unusable, it is true that the model before the iPhone 5s can not be used in 3G lines after 2020 (the end period varies depending on the carrier), so it is true that voice calls cannot be made.Since it loses the most basic functions as a mobile phone, it should be interpreted as being forced to move to another model.
The event that can no longer use this 3G line is due to the end of the 3G service (3G stop) of the communication carrier.Au/KDDI, which was announced earlier, will end the CDMA 1X Win communication service in November 2018 at the end of March 2022.After that, DOCOMO also announced that "FOMA" will be completed in March 2026 and SoftBank will end "W-CDMA" in January 2024, so it cannot be unlocked SIM and supports VOLTE (voice call function using 4G line).The iPhone 5s that is not done will not be able to speak voice calls.The same is true for iPhone 5 and iPhone 5c.
The iPhone from the iPhone 6 to 7 can be selected for 3G or Volte for voice calls, so you can continue to use it after 3G.However, since iPhone 6 is a model that cannot be unlocked SIM, it will be affected by 3G stops if you do not use a SIM card corresponding to VOLTE (some SIMs for au lines handled by MVNO are partially not supported.There is something).
By the way, iPhone 4S, which does not support 4G/LTE, will not be able to use data communication as well as voice calls due to 3G stop.Since the iPhone 4S also has a system update support on iOS 9, let's understand that after 3G stop, it will be a terminal to retire or use the application in the Wi-Fi environment.
