You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Russian_Soviet_Federative_Socialist_Republic

Context:
On December 25, 1991, following the collapse of the Soviet Union, the republic was renamed the Russian Federation, which it remains to this day. This name and "Russia" were specified as the official state names in the April 21, 1992 amendment to the existing constitution and were retained as such in the 1993 Constitution of Russia.

Question:
When was the current name for Russia added to the Russian constitution?

April 21, 1992