This release is old, download the latest version of mergedtesting by clicking on the latest build here: https://github.com/tModLoader/tModLoader/actions?query=branch%3A1.4_mergedtesting and downloading the windows debug build
Release of 1.4_mergedtesting
Install instructions here: https://github.com/Chik3r/tModLoader/wiki