High number of busy waits when using Oracle SecureFiles
Valid from Pega Version 7.2.1
You might experience a high number of buffer busy waits when using Oracle SecureFiles for BLOB storage. An Oracle buffer busy wait occurs when a session cannot access a database block in the buffer cache, because another session is either reading the block into the buffer or changing the buffer. As a best practice, use Oracle 11.2.0.4 or later, because earlier versions have more problems with SecureFiles. In addition, to minimize the number of busy waits, set the hidden Oracle parameter _securefiles_concurrency_estimate to 50, and partition the table by using a composite range hash partition that is based on the pxCreateDateTime and pzInskey columns.
For more information, see Troubleshooting: High number of busy waits when using Oracle SecureFiles.
Email approval and instantiation not supported on multitenant systems
Valid from Pega Version 7.2.1
The Enable email approval check box appears on the General tab of an approval step in Case Designer in multitenant systems. It also appears on the Approval shape in Designer Studio. In addition, in Designer Studio, the Settings tab in Case Designer displays the option to configure email instantiation. However, because configuring email listeners is not supported on multitenant systems, you cannot enable email approval or email instantiation.
Ignore locale settings requires refresh after server restarts
Valid from Pega Version 7.2.1
The Ignore locale check box in operator preferences is selected to display Designer Studio in U.S. English. After a server restarts, screens initially ignore this setting. When the screen is refreshed or reopened, the screen is rendered as expected.
Flexbox-based dynamic layouts not supported for Android 4.4 and earlier
Valid from Pega Version 7.2.1
Flexbox-based dynamic layouts are not supported in Android 4.4 and earlier. When developing applications to be used on devices running Android 4.4 and earlier, use the inline-block layout mode for dynamic layouts.
MBean Javadocs download file
Valid from Pega Version 7.2.1
The Pega 7 Platform MBean Javadocs are no longer provided in the distribution image; however, you can download the 
MBeanJMXJavadoc.zip file that was previously provided in the distribution image.
You can also use JConsole, which is included with the Java Development Kit (JDK), to obtain MBean information. The JConsole MBean tab provides attributes, operations, notifications, and other information on all the MBeans that are registered with the MBean server.
Cannot send mobile push notifications when the Pega 7 Platform is hosted on WebSphere Application Server
Valid from Pega Version 7.2.1
Push notifications are not sent to Android or iOS mobile apps when the Pega 7 Platform is hosted on WebSphere Application Server.
Extract marker file not created at startup
Valid from Pega Version 7.2.1
The extract marker file (PegaRULES_Extract_Marker.txt) is not created at startup, because the rule utility libraries no longer need it. If you used to use the extract marker file to clear the static content file-based cache, to look up lists, or to control starting activities with web nodes, you can delete the contents of the PegaRULES temporary directory instead.
Upgrade/update fails if PostGIS is applied to PegaRULES or PegaDATA schema
Valid from Pega Version 7.2.1
If you use the PostGIS extension to a PostgreSQL database, upgrading or updating the Pega 7 Platform fails if the extension has been applied to either the PegaRULES or PegaDATA schema. PostGIS can be applied to any other schema.
Email listeners no longer copy the email subject text to the email body
Valid from Pega Version 7.2.1
As of Pega® 7.2.1, email listeners no longer copy the email subject text to the email body when the body is empty. If your customer application expects text in the body of the email, the application might fail. You can configure email listeners to copy the subject text to the body by using the following Dynamic System Setting:
Owning Ruleset: Pega-IntSvcs
Purpose: email/copyBodyNoContent
Value: true
For more information, see Creating Dynamic System Settings.
Pega Survey documentation refers to deprecated field
Valid from Pega Version 7.2.1
The documentation for Pega® Survey refers to the Answer Layout field on the Complex Question form, but this field is no longer supported. For more information about the question layout formats that Pega Survey supports, see Pega Survey.