Using an older version of a framework

I currently have version 4.13.0 of the Teensy platform installed.

I want to use version 4.12.0 for a specific project. I made the following change to platformio.ini:
platform = teensy@4.12.0

But that does not work - I get a pop-up notification that says:
command ‘’ not found

How can I fix this?


Please wait a few seconds while PlatformIO downloads new packages. Or, type in CLI (Terminal) pio run and restart VSCode.

The “pio run” command worked, thanks. (It did take a very long time to complete - more than 10 minutes!)

What is your connection speed? Could it be a problem?