Hello,
I will complete 5 years on 15 July. So for extension (hopefully NE), ABH has sendet me the appointment letter on 20 July. It means 4 days I will be without any visa.
I will highly appreciate and thankfull for your reply.
vivek

Hi Vivek,

Answer 1: Don't worry. Its fine.
Answer 2: If still worried then call them and ask.

It doesn't matter if immigration office has no problems with prolongation of your residence permit.

however it's better to apply for a prolongation before your residence permit expires, because if you don't and immigration office doesn't want to prolong your residence permit, you are going to have no valid residence permit till the time they decide what to do with your application => therefore will not be allowed to work in such a case => how to prove that your "Lebensunterhalt ist gesichert"? not an easy thing, or?

immigration offices know that difference very well and therefore make appointments correspondigly, hoping that "problematic people" (the ones that they want to get kicked out of Germany) do not know regulations good enough and get caught on such kind of a bite. doesn't mean anything about their intentions in your case though, 'cause those appointment letters are send out automatically.