The community will undergo maintenance on October 16th at 10:00 PM PDT and will be unavailable for up to one hour.
See here: https://community.ptc.com/t5/PTC-Mathcad-Installation/All-About-Mathcad-Software-Installation/td-p/706433/jump-to/first-unread-message
Mathcad Prime 7.0:
https://www.mathcad.com/en/try-and-buy/mathcad-express-free-download/install
https://free-dl.ptc.com/install/pim_installmgr_mathcad.exe
Mathcad 15 M050:
https://www.ptc.com/-/media/Files/Docs/Mathcad/Mathcad15-EN.zip
