Aptamil doesn't readily mix in water. It forms lumps. Go for other Formula like Nanpro

If his digestion system is fine then no need to change formula milk at this age of 16 months old. Better to give more solids foods now n decrease the intake of milk. Aptamil is best actually...I dont think u need to change it now..

Aptamil is better because it has Prebiotics which is good for baby's gut health and immunity too.

my personal suggestion If she is satisfied to aptamil then don't require to change. Aptamil specific prebiotic mixture has been shown to reduce a wide array of clinically relevant pathogens.

Aptamil. Why are you want to change? If you have seen any prblm, then first consult with your pediatrician, then change.