http://www.qgis.org/en/site/forusers/visualchangelog214/index.html)
General
Feature: Changed behaviour of strpos function
Feature: Zoom to feature with right-click in attribute table
Feature: Speed and memory improvements
Feature: More expression variables
Feature: Better control over placement of map elements
Feature: Paid bugfixing programme
Feature: Field calculator can be used to update feature's geometry
Feature: New expression functions in 2.14
Analysis tools
Feature: More statistics available in merge attributes tool
Feature: z/m values are shown when using the identify tool
Feature: Unified handling of distance and area units and coordinate formats
Browser
Feature: Browser Improvements
Data Providers
Feature: Cache WMS capabililies
Feature: Curved geometry support expanded
Feature: Better handling of time and datetime fields
Feature: Z/M support in delimited text provider
Feature: Transaction groups for postgres editing
Feature: Postgres provider PKI authentication
Feature: Virtual layers
Feature: More file extensions for GDAL and OGR providers file selectors
Feature: Use ST_RemoveRepeatedPoints for server-side simplification with PostGIS 2.2 (or newer) layers
Data management
Feature: Removal of SPIT plugin
Feature: DXF export: option to use title instead of name as DXF layer name in application and server
Feature: Geometry type can be overridden in the vector save as dialog
Feature: Vector joins are now saved within QLR layer-definition-files
Feature: External Resource widget
Feature: N:M relation editing
Digitising
Feature: Configurable rubber band color
Feature: Trace digitising tool
Labelling
Feature: "Cartographic" placement mode for point labels
Feature: Applying label distance from symbol bounds
Feature: Control over label rendering order
Feature: Actual rendered symbol is now considered as an obstacle for point feature labels
Layer Legend
Feature: Paste a style to multiple selected layers or to all layers in a legend group
Feature: Filter legend by expression
Map Composer
Feature: New options for filtering legend elements
Feature: Additional paths for composer templates
Feature: Multiple selection of compositions in manager
Plugins
Feature: Authentication system support for plugin manager
Processing
Feature: New algorithms in 2.14
QGIS geoalgorithms:
GDAL/OGR geoalgorithms:
Feature: Unit Tests Q/A
Feature: Improved toolbox
Feature: Batch processes can be saved and later recovered from the batch processing interface
Feature: More informative algorithm dialog
Feature: GRASS7 v.net modules
Programmability
Feature: Redesign expression function editor
Feature: Store python init code into the project
Feature: New filtering and sorting options for QgsFeatureRequest
Feature: Custom feature form Python code options
Feature: New PyQGIS classes in 2.14
New core classes
New GUI classes
Reusable widgets:
Reusable dialogs:
QGIS Server
Feature: STARTINDEX param in WFS GetFeature Request
Feature: showFeatureCount in GetLegendGraphic
Feature: Option to avoid rendering artefacts at edges of tiles
Feature: Configuration checker in project properties
Feature: WMS INSPIRE Capabilities
Feature: Add short name to layers, groups and project
Symbology
Feature: Size assistant for varying line width
Feature: Support for transparency in SVG color parameters
Feature: Easy duplication of symbol layers
Feature: 2.5D Renderer
Feature: Allow definition of rendering order for features
Feature: Geometry generator symbols
Examples
Translate a geometry
Fill style for polygon border
User Interface
Feature: Attribute table can be refreshed
Feature: Directly set renderer and class symbol colors from context menu in legend
Feature: Edit legend symbols directly from layer tree
Feature: Show/hide all legend items via the context menu