SSP applications contain .ssp files and .ss files, which can be written in either SuiteScript 1.0 or SuiteScript 2.0. However, you cannot have both SuiteScript 1.0 and SuiteScript 2.0 files in the same SSP application.
The components of the URL root of an SSP application are the same for applications written in SuiteScript 1.0 and SuiteScript 2.0. For more details, see The URL Root and its Components.
However, the processes to create an SSP application record and deploy it to domains and websites are different. See SuiteScript 1.0 SSP Applications and SuiteScript 2.0 SSP Applications for more information.
All SSP applications written in SuiteScript 1.0 are available without login. The ability to configure this option, which can be set in a check box on other NetSuite script records, is not currently available for the SSP Application record. This does not apply to SSP applications written in SuiteScript 2.0, which must be explicitly deployed to a site or domain before they are available.