The purpose of the study is to analyze the impact of the Covid-changed learning environment on the assessment of mobile applications for learning STEM disciplines. The study presents the results of the surveys of teachers (n = 38, age 32-52) and students (n = 188, age 19-21) of Sechenov First Moscow State Medical University and Kazan Federal University. The participants evaluated the effectiveness of mobile applications designed to study STEM disciplines. A thorough analysis of three apps dedicated to STEM learning and nine auxiliary niche apps allowed revealing their pros and cons, in particular, expanded student opportunities, the ability to study while staying in the Russian Federation, the availability of a Russian-language version, and the ability to make an appointment (for teachers or students). Due to the increased use of mobile devices by young people, the time frame for completing lessons and motivation to accomplish assignments (tasks related to engineering, solving problems in a notebook, taking notes, completing assignments on the device and in the notebook) were also defined as important. The analysis of mobile apps in the context of distance and blended learning unveiled that, in addition to the well-known criteria, the assessment of such learning means should also make allowance for the possibility to complete tasks outside the digital space, screen time reduction capacity, and accessibility for users. Learning based on a mobile application must be planned to encourage student thinking, the desire to obtain good results, and involvement in project activity.