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:
Wayback_Machine

Context:
In 2011 a new, improved version of the Wayback Machine, with an updated interface and fresher index of archived content, was made available for public testing.

Question:
When was an upgrade of the Wayback Machine released for testing?

2011