Josef Müller-Brockmann's Akzidenz-Grotesk

Hello, I am new to this forum. I am not at all experienced in design or typography, so I apologize in advance.

I noticed the version of Akzidenz-Grotesk used on Josef Müller-Brockmann's posters ( is different from the digital versions currently available from Berthold. To me it looks like the bowl lowercase 'a' is more curved at the top, as it is in Helvetica. Also, the foot (what do you call that?) is much smaller, almost gone. It actually looks a lot like the 'a' in the logo at the top of the website that says "Blanka." Is this not Akzidenz-Grotesk? If so, why are the newer versions different? Is there currently a typeface available that more closely resembles that of the poster?

Thank you for your time!


EDIT: I just found, which has mostly answered my question. But I still have not found a version that has that nice lowercase 'a.'