There was a download of LenMus 5.3.1 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The actual developer of the free software is Cecilio Salmeron. The most popular versions of the LenMus are 5.3, 4.2 and 4.1.
We recommend checking the downloaded files with any free antivirus. LenMus can be installed on 32-bit versions of Windows XP/Vista/7/8/10/11. Commonly, this program's installer has the following filenames: lenmus.exe, lenmus_5.1.exe, lenmus_5.2.exe, lenmus_5.3.1.exe and lenmus_5.3.exe etc. The software lies within Education Tools, more precisely Teaching Tools.
From the developer:
LenMus is an open source program that aims at developing publicly available knowledge, methods and algorithms related to teaching music. It allows you to focus on specific skills and exercises, on both theory and aural training, providing interactive feedback until mastery of each concept is achieved.
You may want to check out more software, such as Typing Instructor Deluxe, DyKnow or Quiz, which might be related to LenMus.