Six runnable methods covering the GroupDocs.Signature 26.9 changes: SHA-2 digests for PDF signatures, AllowExpired and AllowNotYetValid, cryptographic verification, and a LogLevel that finally filters....Six runnable methods covering the GroupDocs.Signature 26.9 changes: SHA-2 digests for PDF signatures, AllowExpired and AllowNotYetValid, cryptographic verification, and a LogLevel that finally filters.