As of A-Shell 6.1.1407, two versions of the PDF-XChange printer driver and associated API are supported: the original PDF-XChange 3.0, and PDF-XChange Printer 2012. For simplicity, we'll refer to these as PDFX3 and PDFX5, the numbers 3 and 5 reflecting the driver version numbers. Although the architecture and internal interface of the new driver is completely different from the original, the A-Shell implementation is upward compatible, such that all existing documents and //PDFX print directives should work the same with either version of the driver. The new driver supports several improvements, described below.
Updated PDF specifications (PDF/A): While PDFX3 supported PDF specifications 1.3 thru 1.6, PDFX5 adds 1.7 and PDF/A-1a thru PDF/A-1u. PDF/A is an ISO-standardized version of PDF designed in particular for the long-term preservation of electronic documents.
Digital Signatures: PDFX3 supported digital signatures, but they had to be pre-configured manually via the driver properties dialogs and could not be validated because of the lack of timestamp support. With PDFX5 you can select system-stored signatures/certificates by thumbprint and specify a timestamp server.
Watermarks: While PDFX3 supported a single watermark if manually pre-configured via the driver properties dialog, PDFX5 adds the ability to create text or image-based watermarks and invoke them on the fly.
Bookmarks: As with watermarks, PDFX3 supported a limited mechanism that required manual pre-configuration in the driver dialogs. PDFX5 supports both template-based (automatically generated when matched to a combination of font, size, style, color) and explicitly inserted multi-level bookmarks with which you can effectively create your own table of contents or index into a complex document or long report.
AES Encryption: PDFX3 supported only 40 and 128 bit RSA encryption; PDFX5 adds 128 and 256 bit AES, the latter of which will presumably be used in the PDF 2.0 standard and is currently used by Adobe Acrobat.
Booklet Mode printing: auto-arrangement of the pages to form a booklet.
Sheet Scaling/Positioning: You can define sheet sizes independent of the paper, with options for positioning and/or scaling to the paper (including scale to fit). This is particularly useful when adding meta text to documents, such as headers, footers, signatures, etc.
Headers and Footers: You may define headers and footers (with independent left/center/right elements and full control over font and positioning), with support for macros such as Page n of m, file name, date. Combined with Sheet Scaling, this allows you to effectively add headers and footers outside the original area of the page.
Updated Windows Compatibility: Windows 8, Server 2012, etc.
Optional Viewer / Editor: Offers an alternative to and possible advantages over the standard Acrobat Reader.
Improved internal architecture: Allows for bidirectional communication with the driver, creating a more flexible base to build additional features on in the future.
General: Several years worth of incremental improvements, refinements and fixes.
