There have been some changes to the tier 1 category with graduate entrepreneur visas being substituted with start-up visas. The application process remains similar. You will still need an endorsement to apply. However, you will be able to chose the most suitable endorsing body depending on your needs. You will be pleased to know that majority of such bodies are operating in the tech field. The fact that you graduated three years ago should not be an issue. And you should be able to apply even despite you field of study is different from what you are planning to do, especially, provided that you have work experience in the field.
