This has been announced several times in the past two years [0][1]. Now that v8-inspector has taken over as a viable alternative, the old and unmaintained JSON debug API is now finally being removed from V8 [2]. I suggest migrating over to the inspector protocol if your tool talks to node/v8 via the legacy JSON debug API.

[0] https://docs.google.com/document/d/1M8DdgDldglYjQJ1mu0yBzwgR6lCX-ZKS_hxAJiCLT34/edit
[1] https://github.com/v8/v8/wiki/Debugging-Protocol
[2] https://chromium.googlesource.com/v8/v8/+/81a64aa5488602e4643f1ecc3beeddb8828a853c