I know nothing about Mangoes apart from my one (successful) effort at growing a seed and seeing them growing around the world when away on holiday. But my impression is that new growth is often, if not always, pale and or pinkish in colour. If they stay pale then you may have a problem.

The potting soil is not peaty but maybe you are right. Maybe I need to repot. The leaves haven't changed color yet. They are still pale. Do you think calcium deficiency?

No,not a calcium looking problem. Just ordinary lack of nitrogen and iron and..all else fresh soils will give. I haven't seen a photo of the whole plant and pot. If the pot is still the right size- fertilize. If its outgrown the pot..move it up in size.

Thanks for this great input. I will shot a pic of the tree. I don't think it's pot bound though as I have potted this tree not long ago, this spring to be precise. I have fertilized it 7-5-4 and foliar feed on 4th of sept. The foliar food had enough iron and other micronutrients. So I really consider to change the soil.