Can I use my iText 5 license with iText 7?

No you can't. This is also true for the reverse, you can't use an iText 7 license for iText 5.

No you can't. Doing so will throw a LicenseKeyException and you won't be able to use it. This is also true for the reverse, you can't use an iText 7 license for iText 5.

If you do want to have a license for the other version, please contact our sales department.