| Feature | OData v2 | OData v4 |
|---|---|---|
| Release Year | 2010 | 2014 (OASIS Standard) |
| Standardization | Microsoft proprietary | Official OASIS and ISO standard |
| Data Format | Atom (XML) and JSON (limited) | Optimized JSON (no Atom), cleaner structure |
| Metadata Format | CSDL in XML | CSDL in XML and JSON |
| Navigation | $expand (basic support) | Improved $expand with deeper levels |
| Actions/Functions | Limited | Fully supported, standardized |
| Enum Support | Not available | Supported |
| Containment | Not supported | Supported (better nested structures) |
| Batch Requests | Multipart MIME | Multipart MIME (more refined) |
| Type System | Less flexible | Richer type system with inheritance & complex types |
| Annotations | Minimal | Strong support for annotations |
| Adoption | Legacy systems (e.g., older SAP services) | Recommended for new development |
OData v4 is a more modern, flexible, and standardized protocol, while v2 is still used in many legacy systems but lacks advanced features.