Long live ReCaptcha v1!
Thursday, April 5. 2018
Ok. It's dead! It won't live long.
That seems to suprise few people. I know it did surprise me. 
Google has had this info in their website for couple years already:
What happens to reCAPTCHA v1?
Any calls to the v1 API will not work after March 31, 2018.
Starting in November 2017, a percentage of reCAPTCHA v1 traffic will begin to
show a notice informing users that the old API will soon be retired.
Yup. This blog showed information like this on comments:
Now that the above deadline is gone, I had to upgrade S9y ReCaptcha plugin from git-repo https://github.com/s9y/additional_plugins/tree/master/serendipity_event_recaptcha. There is no released version having that plugin yet.
Now comments display the v2-style:
To get that running, I simply got the subdirectory of plugins/serendipity_event_recaptcha with the content from Github and went for settings:
I just filled in the new API-keys from https://www.google.com/recaptcha and done! Working! Easy as pie.
Update 5th April 2018:
Today, I found out that Spartacus has ReCaptcha v2 plugin available to S9y users. No need to go the manual installation path.
