After starting kibana seems to be working fine. However, I noticed that in newer ROR version 1.61 Free after every 10 minutes there are logged events about Activation Key not being found, which in older version was logged once just before start.
Nov 21 07:32:52 host kibana[X]: [ROR COMPAT] store.js patch status: VERIFIED.
Nov 21 07:42:49 host kibana[X]: [07:42:49:610] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=d9b33af6-XXX] Cannot get the encrypted activation key from Kibana... Status code: 404
Nov 21 07:42:49 host kibana[X]: [07:42:49:616] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=d9b33af6-XXX] No Activation Key found. That's OK. Defaulting to Free license.You can add your own Activation Key later.
Nov 21 07:42:49 host kibana[X]: [07:42:49:617] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=d9b33af6-XXX] Visit ReadonlyREST Customer Portal at https://readonlyrest.com to get a trial Activation Key.
Nov 21 07:52:49 host kibana[X]: [07:52:49:611] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=dbac2c8f-XXX] Cannot get the encrypted activation key from Kibana... Status code: 404
Nov 21 07:52:49 host kibana[X]: [07:52:49:618] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=dbac2c8f-XXX] No Activation Key found. That's OK. Defaulting to Free license.You can add your own Activation Key later.
Nov 21 07:52:49 host kibana[X]: [07:52:49:618] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=dbac2c8f-XXX] Visit ReadonlyREST Customer Portal at https://readonlyrest.com to get a trial Activation Key.
Nov 21 08:02:49 host kibana[X]: [08:02:49:614] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=dbac2c8f-XXX] Cannot get the encrypted activation key from Kibana... Status code: 404
Nov 21 08:02:49 host kibana[X]: [08:02:49:622] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=dbac2c8f-XXX] No Activation Key found. That's OK. Defaulting to Free license.You can add your own Activation Key later.
Nov 21 08:02:49 host kibana[X]: [08:02:49:622] [info][plugins][ReadonlyREST][LicenseService][x-ror-correlation-id=dbac2c8f-XXX] Visit ReadonlyREST Customer Portal at https://readonlyrest.com to get a trial Activation Key.