v055c: Check for blocklist updates for RDNS+ does not work?

[ignoramous]

A user writes,

• I don't use On-device blocklists.
• "Prompt on blocklist updates" is enabled.
• Have been using the website version, till v055c over the last 2 years.
• And have been using RDNS Plus mostly.

I have never got any prompts update the blocklist [version].

[ignoramous]

See also: #564