This question already has an answer here:
After Completion of my Master in Germany, I was issued a Work Permit based on Job contract where salary was not exclusively mentioned but TVL was mentioned.
So I was told by officer , there is no difference in Work Permit and Blue Card when you have degree from German University and you will be eligible for permanent residence after 22 months.
But reading the differences on portals, I am bit confused. Should I change it to Blue Card? As 1 year already passed , will it effect my duration to permanent residence?