Hi @tmndungu, welcome to the ODK forum, we're glad you're here! Thanks for adding a picture to your profile, we think it helps build community. If you get a chance, we'd appreciate it if you introduce yourself on this other forum thread.
I believe those docs have been transitioned to docs.getodk.org and can be found at
https://docs.getodk.org/openrosa/#openrosa-1-0-apis (and with the Form List API docs at https://docs.getodk.org/openrosa-form-list/)