### Installation and System Requirements

Remote object persistence support is included in the standard Cayenne distribution. System requirements are the same as for the rest of Cayenne, and there is no special installation procedure. Check the Installation chapter of Cayenne User Guide for details.

### Server Jar Files

Cayenne web service is no different from a regular Cayenne application, so it requires `cayenne-server.jar` and all standard dependencies. The only additional required third-party library is Hessian:

- Hessian Library, version 3.1.6.

### Client Jar Files

On the client `cayenne-client.jar` is needed. This is a stripped-down version of Cayenne runtime. The following third party dependencies are needed (all included in "lib/third-party" directory of the distribution, except for hessian):

- Apache Commons Logging, version 1.1.
- Apache Commons Collections, version 3.1.
- Hessian Library, version 3.1.6.

Note that there can be issues with running different versions of Hessian on the client and server since the Hessian protocols sometimes change between even minor releases. We recommend you keep them matched or look at the Hessian source to decide whether you might have compatibility issues.

| Hessian Versions Cayenne 3.0 works correctly with Hessian 3.0.x and 3.1.x. Hessian 4.0.2 has a bug that stops ROP. Hessian 3.2.x is binary incompatible with other versions and cannot be used.