On 24 July 1914, Laszlo Count Szogyeny, the Austro-Hungarian Ambassador to Germany (pictured), sent a coded telegram to Leopold Count Berchtold, the Austro-Hungarian Minister of Foreign Affairs. In his telegram, Szogyeny informs Berchtold that he delivered a copy of the Austro-Hungarian ultimatum to Serbia to the German Minister of Foreign Affairs.
Count Szogyeny to Count Berchtold. Berlin, 24 July 1914.
In accordance with your Excellency’s instructions, I handed the Note to Servia [i.e. the Austro-Hungarian ultimatum to Serbia] to the German Minister of Foreign Affairs [Gottlieb von Jagow] yesterday, and this morning, obeying your Excellency’s instructions by telegram, I gave notice of the change in the expiration of the term to 18:00.
Herr von Jagow sends his thanks for this information and assured me that the German government agrees entirely with the contents of the Note.
Source: 1919 Austro-Hungarian Red Book, with minor edits.