I believe you need to pay a license to use it.
You can contact kirill@annoto.net who was at the Open edX conference last week. I think he could address your questions.
Hi!
I will be happy to assist you,
Annoto xBlock is compatible with all the latest versions and can be updated to support any particular version
Annoto is a subscription-based license Here you can find more information on the Annoto capabilities
If you need any additional support please let me know, you can contact me at this email: Hen@annoto.net
Hen