Simpleforms is an extension to create contact forms for your bolt site. With those forms visitors can send you email messages from the website.
This release is completely rewritten to make the boltforms extension do all the work.
This means that boltforms will be installed when you install simpleforms too.
The simpleforms configuration is less elaborate than the boltforms configuration.
Some things that were possible in simpleforms earlier are not possible anymore in this version. If you want to upload file attachments or want to save the form data to the database you must use boltforms now.