This depends on which version of iText you are using:

  • If you're using iText 7 Suite version 7.2 (or newer) you'll need to use version 4.x.y of the license key library
  • If you're using iText 7 Suite version 7.1.17 (or older) or iText 5.5.13 (or newer) you'll need to use version 3.x.y of the license key library
  • If you're using iText 5.5.12 (or earlier), you'll need to use version 1.x.y of the license key library

Please use the latest version within the appropriate major version to have the latest features and bug fixes available.

For more information, see the license key and license key library installation guide.