Need your advice

Anybody who own diesel car from 2011 or earlier and want to keep it what are the safety measures you are taking to protect the engine life of your vehicle. Many of my friends who are into cars are suggesting me to sell my 2011 Endeavour 4X2 Diesel as they are saying that BS6 or above compliant diesel would not work in older vehicle engine. I really don’t want to sell this car of mine as it has everything I need per my usage and drive. Thanks in advance. 😊