|1||3|| * The style of a selected feature, in the past, was treated as an explicit setting of all the properties of the style of the feature. In OpenLayers 2.6, the 'select' style is instead an *extension* of the existing style. This means that if you have a feature which is styled with an externalGraphic, and you select it, you will still see an externalGraphic unless you explicitly mark that property as an empty string, for example. This allows for features to change only some properties when selected: if you have a set of features with varying pointRadius style attributes, you can set your select style to 'strokeColor': 'red', and the feature will keep its current size, and only change stroke style.
|2||4|| * The GeoRSS and Text layer data loading has been refactored slightly. Instead of loading data on instantiation, this load now happens the first time that the layer is visible and moved (via the moveTo command). If you'd like to mimic the old behavior, you can call layer.loadRSS() or layer.loadText() immediately after creating the layer. However, it would be better to tie your functionality to a loadend event from the layer: this way, you can be notified when the data is actually loaded, since it happens asynchronously. In either case, in order to take advantage of reprojection support, you will need to first ensure that a map is set on the layer by adding the layer to a map.