Forum Discussion
Sorry that you couldn't find the REST API reference for BIG-IQ v5.2. Here is the link to that: https://devcentral.f5.com/wiki/BIGIQ.APIRef.ashx
Please note: "THE BIG-IQ APIs ARE DESIGNED AND TESTED FOR VERSION 5.2. ANY USAGE ON PREVIOUS VERSIONS IS NOT SUPPORTED"
Regarding licensing/re-licensing BIG-IPs (managed and unmanaged) from regkey pools via the BIQ-IQ, please refer to this sub-reference from the above link (BIG-IQ licensing - Registration Key Pools): https://devcentral.f5.com/wiki/BIGIQ.APIRef_license-registration-key-pool.ashx
The relevant section is titled "Add, or license, a device as a member of a BIGIQ license registration key pool." The relavant JSON object is "post_regkey_members_body".
Example below: please note that I have enabled basic-auth (disabled by default from BIG-IQ v5.1 - https://support.f5.com/csp/article/K43725273)
curl -sku admin:secret \
https://BIG-IQ-managment-IP/mgmt/cm/device/licensing/pool/regkey/licenses//offerings//members \
-X POST -d '{deviceAddress:BIG-IP-IPaddr, username: "admin", password:"secret"}'
Hope this helps.
Let me know of any questions in this regard.