I am using Arduino GSM shield displayed below which requires mini-SIM card (25mm long and 15mm wide). This type of SIM card is not any more avaliable in my country. Can you suggest a solution to solve this problem
Lots of places are phasing out the older technology GSM networks (2G etc.). Are you sure that this old board will still work in your local mobile networks ?
I can't really because that depends on what network technologies / frequencies are available in your area. You may be lucky in that the one you already have still works in you area. What I can say is that you have to be extremely careful when selecting such a shield/module to ensure compatibility and these may have regional variants. Sometimes the documentation provided by the manufacturers is not enough to give a definitive answer.
@lastchancename on this forum has been known to recommend/work with SIM7600 modules