recaptcha v1 vs v2

What are the differences between recaptcha v1 and v2?Other than the obvious visual differences, the only other features in v2 that I could find are:- how many No CAPTCHAs were rendered per day- a site spam index chartsee: http://bit.ly/1CFgIuM, is v1 still supported? -- You received this message because you are subscribed to the Google Groups "reCAPTCHA" group. To unsubscribe from this group and stop receiving emails from it, send an email to recaptcha+unsubscribe@googlegroups.com. To post to this group, send email to recaptcha@googlegroups.com. Visit this group at http://bit.ly/1dkFnYd. For more options, visit http://bit.ly/P65DvS.

Re: new reCAPTCHA version 2 support for Play/Scala web apps