You can install an old version of an npm package using the @ syntax:

npm install <package>@<version>

Example:

npm install cowsay

installs version 1.3.1 (at the time of writing).

Install version 1.2.0 with:

npm install [email protected]

The same can be done with global packages:

npm install -g [email protected]

You might also be interested in listing all the previous version of a package. You can do it with npm view <package> versions:

❯ npm view cowsay versions

[ '1.0.0',
  '1.0.1',
  '1.0.2',
  '1.0.3',
  '1.1.0',
  '1.1.1',
  '1.1.2',
  '1.1.3',
  '1.1.4',
  '1.1.5',
  '1.1.6',
  '1.1.7',
  '1.1.8',
  '1.1.9',
  '1.2.0',
  '1.2.1',
  '1.3.0',
  '1.3.1' ]