The tag ITUNESADVISORY doesn't work. Since the new Update it doesn't work anymore. Please do a update or help me. :unsure:

Could you be a little more specific what does not work?
To which update do you refer?
Where do you see that it does not work any more?
What have you done to test it?

Since the update 2.72 it doesn't work anymore (the newest update). I saw it on, that the sign comes not anymore on iTunes when I tag a m4a. I tried all. But I think that I did something wrong because it's a new update maybe. So can you please describe what I have to do, that I become that "Explicit" sign in iTunes?

See the help pages for the values

Then check how iTunes updates its data. There are scripts around that do that or you have to select that track and call the information or delete it from and add it again to the library.
If all this does not update the display in iTunes, try to tag a file in iTunes and see how that shows up in Mp3tag.