"Unfortunately, as a result, FingerprintJS was no longer so easily accessible to the developer community. We heard your feedback — now, all new code updates to FingerprintJS are under the MIT license. We want to ensure the latest in browser fingerprinting technology is accessible and available to all developers and businesses to help fight against fraud."

Read: The usage dropped significantly.

What allows them to switch back is hidden in the accordion at the bottom:

   Why are you making FingerprintJS v5.0 available under an MIT license now?
   [...]
   We have made substantial improvements to Fingerprint Pro so that competitors relying on FingerprintJS for browser fingerprinting is no longer a concern.

Comparison seems to be at https://fingerprint.com/github/, scroll to bottom for "Feature comparison" table.