As Pega Infinity™ software advances, Pega is committed to providing software upgrades with minimal disruption so both clients and their customers can continue to access and use Pega applications throughout the entire upgrade process. To achieve this goal, the development process follows a near zero-downtime standard that attempts to ensure that the latest Pega software features and enhancements impact client applications as little as possible from release to release. The near zero-downtime standard sets the following goals:

• Changes allow client applications to run during upgrades.
• Changes are backwards compatible for clients applications that are based on Pega Infinity.
• Performance and security enhancements may impose a minimal upgrade impact, since application stability and client security are our highest priorities.

Pega supports both a major upgrade (7.x to 8.x) and a minor upgrade (8.x to 8.y) of the Pega Platform™ software versions and any Pega applications that are running in your system. For details about the process and standards for minor Pega software upgrades, see The minor upgrade process for Pega Infinity 8.4 and later.

As part of its near zero-downtime commitment, Pega has reviewed the features and fixes in Pega Platform 8.4 and has identified the following areas where a minor upgrade to Pega Infinity 8.4 will have an impact. Click each area to learn about the impact and a workaround for it:

• Increased visibility of strategy design changes with simulation batch tests
• Relationships between elements of microjourneys in application inventory
• Pega Express Delivery Approach in App Studio for successful microjourneys
• Personalized views in table layouts
• Custom application URL alias in the application definition
• Rules can no longer access Pega internal Java packages
• Support for the JSON Web Token Bearer grant type for accessing external APIs
• PDF/UA support
• Updated default dynamic system settings for requestor pools