Below is the prep work for migrating from ISE2.4 to ISE3.1+ for AWS, and the migration steps are here, but I have summarize them below.

Cisco ISE is available as an infrastructure-as-code solution leveraging AWS CloudFormation making the deployment of ISE a very light lift. I’ll be walking you through how to deploy ISE on AWS in a later post.

Step 1 – Base, Plus, Apex, and Device Admin licenses need to be migrated to Smart Licenses
Step 2 – VM licenses need to be converted
Step 3 – Migration can occur. Once licenses are prepped and converted, you go to the AWS Marketplace ISE BYOL listing and choose your deployment size. 

ISE Licensing

1. AWS ISE requires ISE 3.1+
   1. If upgrading to 3.1 from an existing 2.X release, it is required that a customer migrate their existing licenses to the new licenses and then upgrade to the 3.0 release. I.e. These are the Base, Plus, and Apex license that need to be upgraded. Device Admin licenses are grandfathered and need to be upgraded to a Smart License as well.
2. This requires a Cisco Smart License Account. 
3. Please refer to the Migration Guide for instructions.

ISE VM – You need to register the VM Common license for ISE 3.1 and later.

1. Customers need to migrate their ISE License to the new “Common License.”
   1. To migrate the legacy VM license to the VM Common license, customers need to obtain the $0 upgrade Product ID (PID), “L-ISE-VMC-UPG=, from Cisco. This is the same PID regardless of what current size of VM license you have today.
   2. https://www.cisco.com/c/en/us/products/collateral/security/identity-services-engine/ise-licensing-migration-guide-og.html

2. To obtain a VM Common License for a net new deployment you’ll need the new VM PID, “R-ISE-VMC-K9=” Refer to the table below for a 1:1 mapping.

These VM licenses are valid in Cisco ISE 3.0 and earlier releases. Again, when you upgrade your Cisco ISE to Release 3.1, you will need to have VM Common license.  

Upgrade From	Upgrade To	Ratio
R-ISE-VML-K9=	R-ISE-VMC-K9=	1:1
R-ISE-VMM-K9=	R-ISE-VMC-K9=	1:1
R-ISE-VMS-K9=	R-ISE-VMC-K9=	1:1

How to migrate license

To migrate the legacy VM license to the VM Common license, customers need to obtain the $0 upgrade PID, “L-ISE-VMC-UPG=,” in CCW. See ISE Licensing Migration Guide for the detailed process.

Support for VM and License

Q. What support do customers receive with the new ISE licenses?

A. The same as with current subscription licenses. With the new ISE software licenses, customers receive embedded SWSS—which covers 24x7x365 Cisco Technical Assistance Center (TAC) support and software updates. However, now Essentials will also have this support.

More Question and Answers here

Support associated with the legacy VM licenses

When customers upgrade the version of their legacy VM to VM Common license, they can continue to receive support based on the support contract purchased on legacy VM license PID. They can renew the support until the legacy VM license PID is EOL and reaches the last service renewal date per the EOL bulletin. There is no support for migration. For seamless support, the customer should request the legacy VM PID to be replaced with the desired VM PID in order to renew and receive support.

Mike