Hi
Subscription key have not been utilized since version 6.6, the first new license format was in 6.7 and the current license format was introduced in 6.8.
What format do you have on your current licenses?
If you have bought the ClearPass with the old license model and never converted the licenses since 2017 you should find the subscription ID under ClearPass Legacy licenses.
To be able to convert you need an active support agreement.
If you have converted to 6.7 format you need to convert from 6.7 to 6.8+ format

If you already have ClearPass 6.8+ format on your licenses you don't need to convert it for 6.11 installation.
But it's one more twist, if the original ClearPass was in the old pre 6.7 license model you need to convert the SKU's to the new SKU's
------------------------------
Best Regards
Jonas Hammarbäck
MVP Guru 2024, ACEX, ACDX #1600, ACCX #1335, ACX-Network Security, Aruba SME, ACMP, ACSA
Aranya AB
If you find my answer useful, consider giving kudos and/or mark as solution
------------------------------