GeoServer 2.7

What's new in this version:

Color composition and color blending:
- These are two new extensions to the rendering engine that allows for greater control over how overlapping layers in a map are merged together. Instead of just placing layers on top of others (with or without transparency), there is now a range of filters and effects, such as “multiply”, “darken”, and “hard light”.

Relative time support in WMS/WCS:
- GeoServer has long had the ability to specify dates/times in requests to subset data. Up until now these dates/times needed to be absolute. Support has now been added for specifying relative time.

WPS clustering:
- There are quite a few improvements to the Web Processing Service module, courtesy of Andrea Aime and GeoSolutions. (Please note that WPS is still an extension.)
- GeoServer has a new WPS extension point allowing GeoServer nodes in the same cluster to share the status of current WPS requests. This is particularly important for asynchronous requests, as the client polling for the progress/results might not be hitting the same node that’s currently running the request.
- This initial implementation leverages the Hazelcast library to share the information about the current process status using a replicated map.

WPS security
- GeoServer now has the ability to connect WPS processes to the standard role-based security system. This means that administrators can now determine what users and groups can access or execute, making WPS usage safer and more secure.

WPS limits:
- In addition to limiting the users and groups that can access WPS processes, GeoServer now also has the ability to set WPS input execution limits (such as timeout values), ensuring that a runaway process can’t cause a system to fail due to utilizing too many resources. Limits can be set globally and on a per-process basis.

WPS dismiss:
- A client that connects to the WPS now not only has the ability to execute processes, but also the ability to dismiss/kill processes. Also new is the ability for the administrator to see the current processes that are being executed on the system.

CSS extension refresh:
- The popular CSS extension, originally written by David Winslow of Boundless, allows users to style layers using a CSS-like syntax instead of SLD. This extension has now been entirely rewritten in native Java. The functionality remains the same, though with improvements in speed and stability.

New CSS workshop:
- There is also now a full workshop-sized tutorial devoted to using CSS in GeoServer. This expands upon the basic tutorial, and goes into greater detail, providing a powerful learning resource for anyone who wants to learn how to style maps with CSS.

Cascade WFS Stored Queries:
- Thanks to Sampo for adding support for cascaded WFS stored queries.