Okay, what is advanced? Just because the equipment is made recently, automatically makes it "advanced"?
Let's take some examples.
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This is M2 Browning HMG, whose design is unchanged since WW1. Pretty obsolete piece of equipment, eh? Yet more than half of world military use it today.
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Carl-Gustav RCL, my favourite type of infantry weapon in Indian arsenal. It was designed just after WW2 (1948). Must be an obsolete equipment right? But now US military and special forces are placing order for it.
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Artillery is a relatively simple piece of equipment. 105mm IFG went numerous improvements in Indian arsenal, and its metallury has also been improved to increase its barrel-life and make it lighter. It is hardly obsolete.