downgrade

In computing, downgrading refers to reverting software (or hardware) back to an older version; downgrade is the opposite of upgrade. Programs may need to be downgraded to remove introduced bugs, restore useful removed features, and to increase speed and/or ease of use. The same can occur with machinery.

An example of a downgraded program is Gmax, a downgraded version of 3ds max used by professional computer graphics artists, free to download and simplified for ease of use.