The OIE upgrade is “Eligible with warning” due to the potential impact on user experience.

Potential Experience Impact

Level of Effort for Upgrade to Parity: High - CIAM (customer experience) has a low tolerance for any impact to the User Experience changes that are associated with the improvements of OIE. Hence, we want to be sure they investigate a bit further to understand the limited impacts during the upgrade.

The following guides help highlight the feature changes:

• General Upgrade Guidance: Upgrade to Okta Identity Engine
• Developer Focused Guidance: Identity Engine upgrade overview
• Upgrade Sign-In Widget: Upgrade the Okta Sign-In Widget 

Verify

• Account Activation Flow [Email Templates]

  • [Admin/API/Directory Initiated]

    • fromURI in email template

    • Payload activationToken into Custom AuthN API

  • [Custom SDK/Management API]

    • Custom/External Email?

    • fromURI in email template

    • Payload recoveryToken into Custom AuthN API

• Email Template modifications Activation & Recovery

  • Used to divert to the Custom Embedded application

  • Activation Templates 

  • Recovery Templates 

• Custom Password Recovery Flow

PRE-Upgrade

• No changes are REQUIRED prior to upgrade to Okta Identity Engine

• The /authn API will continue to work in a "classic mode" in Identity Engine to make the upgrade transition easier

Post-Upgrade Parity (Classic Mode)

• Discovery Dependent: Email Templates

Post-Upgrade Enhanced Experience (OIE Functionality)

• Option 1: Shift from Classic SDK/API to Federation Model (Okta hosted) 

  • Advancements in Identity Engine extensibility may deprecate the need for a customer-hosted sign-in experience.

• Option 2: Shift from Classic SDK/API to Embedded SDK

• Option 3: Shift from Classic SDK/API to Direct Authentication API

A good starting point for building an understanding of Redirection vs. Embedded Authentication models is Okta deployment models - redirect vs. embedded.