Diapers question!

ca

So my 5 months old baby is wearing huggies little movers size 6 and they fit okay but they don’t work for me during the night because we are having some leaks in the morning

Is there a size 7 so he can wear them during nighttime or should i buy night time diapers?

Do size 7 even exist?

And after my baby grows up size 6 what’s next?