OData Version 4.0 is the current recommended version of OData. OData V4 has been standardized by OASIS and has many features not included in OData Version 3.0.

Go to OData Version 4.0

• OData Version 3.0 Core Protocol | PDF
• OData Version 3.0 Common Schema Definition Language (CSDL) | PDF
• OData Version 3.0 Url Conventions
• OData Version 3.0 ABNF
• OData Version 3.0 Batch Processing
• OData Version 3.0 Atom Format
• OData Version 3.0 JSON Verbose Format

To get started learning OData V3, begin by reading OData Version 3.0 Core Protocol and progress to the other documents as required by your scenario.