Error in brewlet if Warning: Calling the `appcast` stanza is deprecated! Use the `livecheck` stanza instead

[UlTriX]

If your homebrew generates the message "Warning: Calling the appcast stanza is deprecated! Use the livecheck stanza instead." for a package brewlet will generate a JSON parse errorand will not work.

[zkokaja]

Hi, how did this error happen? Is it specific to a formula? I'm not familiar with appcast or livecheck. Thanks