set Enable Ltv
Enable or disable embedding Long-Term-Validation (LTV) in the signature which upgrades signature to PAdES B-LT. LTV will check each certificate for validity and if successful will keep that information in the document. LTV information can also be added later using com.pspdfkit.document.PdfDocument.addLongTermValidation. Note, enabling LTV may result in an HTTP network call which may result in you needing to enable the use of cleartext traffic in your app.
Default value is true.