This tutorial shows you how to work with the Scan and Optimize features in Acrobat 9. See what the all-new Acrobat DC can do for you.

Download a free trial of the new Acrobat.

Understanding PDF compatibility levels in Acrobat 9

Learn how change the PDF version in Acrobat 9 by switching to a different preset or choosing a compatibility option in PDF Optimizer.

By Adobe – July 13, 2009

When you create PDF files, you decide which PDF version to use. You can easily change the PDF version to make your PDF document compatible with Acrobat 4, 5, 6, 7, 8 and 9 by switching to a different preset or choosing a compatibility option in PDF Optimizer.

Generally, unless there’s a specific need for backward compatibility, use the most recent version (in this case, Acrobat 9.0 and later). The latest version includes all the newest features and functionality; however, if you’re creating documents that will be distributed widely, consider choosing Acrobat 6.0 or Acrobat 7.0. Using one of these versions ensures that all users can view and print your document.

Here are two ways you can select compatibility levels:

In Acrobat Distiller, select Settings > Edit Adobe PDF Settings > Compatibility. Select a compatibility level.
In PDF Optimizer, select Advanced > PDF Optimizer > Make Compatible With. Select a compatibility level.

The following table compares some of the functionality in PDF files created using the different compatibility settings.

Acrobat 4.0 (PDF 1.3)	Acrobat 5.0 (PDF 1.4)	Acrobat 6.0 (PDF 1.5)	Acrobat 7.0 (PDF 1.6), and Acrobat 8 and Acrobat 9 (PDF 1.7)
PDFs can be opened with Acrobat 3.0 and Acrobat Reader 3.0 and later.	PDFs can be opened with Acrobat 3.0 and Acrobat Reader 3.0 and later. However, features specific to later versions are sometimes lost or not viewable.	Most PDFs can be opened with Acrobat 4.0 and Acrobat Reader 4.0 and later. However, features specific to later versions are sometimes lost or not viewable.	Most PDFs can be opened with Acrobat 4.0 and Acrobat Reader 4.0 and later. However, features specific to later versions are sometimes lost or not viewable.
Cannot contain artwork that uses live transparency effects. Any transparency must be flattened before converting to PDF 1.3.	Supports the use of live transparency in artwork. (The Acrobat Distiller feature flattens transparency.)	Supports the use of live transparency in artwork. (The Acrobat Distiller feature flattens transparency.)	Supports the use of live transparency in artwork. (The Acrobat Distiller feature flattens transparency.)
Layers are not supported.	Layers are not supported.	Preserves layers when creating PDFs from applications that support the generation of layered PDF documents, such as Illustrator CS and later or InDesign CS and later.	Preserves layers when creating PDFs from applications that support the generation of layered PDF documents, such as Illustrator CS and later or InDesign CS and later.
DeviceN color space with eight colorants is supported.	DeviceN color space with eight colorants is supported.	DeviceN color space with up to 31 colorants is supported.	DeviceN color space with up to 31 colorants is supported.
Multibyte fonts can be embedded. (Distiller converts the fonts when embedding.)	Multibyte fonts can be embedded.	Multibyte fonts can be embedded.	Multibyte fonts can be embedded.
40‑bit RC4 security supported.	128‑bit RC4 security supported.	128‑bit RC4 security supported.	128‑bit RC4 and 128‑bit AES (Advanced Encryption Standard) security supported.