Some agencies offer a shorter version of Sprint, which lasts 4 days. It was presented as the "Design Sprint 2.0". For the last 3 years, we have experimented a lot and tried different types of Design Sprint.
Based on our experience the type of Sprint we recommend is traditional 5-day Design Sprint. As it is described in Jake Knapp's and John Zeratsky's book and applied at Google Ventures. Therefore, it is important to say that before writing the book, GV teams tested the process during more than 150 Sprints before finding the right recipe.
There is a pragmatic and commercial reason why companies want to offer a shorter, 4-day version of Sprint. It is always difficult to bring together important stakeholders for several days in a row (3 days for the workshop part in traditional Design Sprint). Because of this it is logical to try to condense this phase over 2 days. In Design Sprint 2.0 days 1 and 2 (Map and Sketch) are gathered in one day.
This implies a fast pace from the start of the Sprint, less time to understand the issues and especially a simplified Mapping exercise, see nonexistent. The risk at this stage is to misidentify the problem. In order to overcome these shortcomings, some prefer to prepare a basic version of the map beforehand or carry out a "problem framing" workshop upstream. Finally, a well-prepared 4-day Design Sprint looks furiously like a 5-day.
User Experience (UX) Workshops
In some cases, it's not possible to gather the right people for 5 days, or the challenge does not require a complete Design Sprint. Usually, it is the case of a follow-up Sprint. It is possible to use Design Sprint exercises, combine them wisely to create Custom 1, 2 or 3 day Workshops. In this case, we avoid calling it Design Sprint, but simply - User Experience (UX) Workshops