- 1950 Purchase of café, wine bar and guesthouse with 6 beds from the Karl and Margret Mayr family.
- 1959 Extension of the bed wing and spa department with Kneipp cures/ mud packs and baths.
- 1968 /69 Extension of swimming pool and bed wing.
- The hotel swimming pool was one of the first of its kind in the Allgäu.
- 1986 Purchase of the Burgstadl (old clubhouse) and conversion into a cosy function room for celebrations and conferences.
- 2004 Takeover by Karl and Ingrid Mayr
- 2005 Addition of new wellness + sauna area "AlpenSpa Zugspitzblick" and renovation of hotel bathrooms.
- 2018 The next generation - Michi and Thomas Mayr both return to the Mittelburg - their parents' family business.
- Michi completed his training in tourism and leisure and then travelled around Munich working in hotels and restaurants to bring creativity and new ideas to the Mittelburg.
- Thomas studied Tourism Management at the MCI in Innsbruck, where he successfully completed his Master's degree. He gained experience abroad in Portugal and Australia with the aim of leading the Mittelburg into a creative, modern future.
- 2018 Renovation of the swimming pool area
