The tax return program known as H&R Block is powered by files known as T11 files. That is to say that the 2011 version of the H&R Block software was powered with this type of file. The company has since updated the files that they use time and time again over the years. However, the T11 files that they used at the time were very important to the overall functioning of the tax return services that H&R Block has to offer to people who use their programs. You have to take special consideration of the T11 files that are a part of the overall H&R block system. It is very important that such files get the respect that they deserve as they are often considered to be the building block of tax return programs that have come to be in the future. This is why T11 files are so important.