QGIS Changelog: Entries -

You can now control both horizontal and vertical margins for label items. Previously only a single margin setting would apply to both horizontal and vertical margins. This change allows users to specify different horizontal and vertical margins.
You can now specify negative margins for label items, allowing text to be drawn slightly outside of a label item's bounds. This is desirable for aligning label items with other items while allowing for optical margin alignment for the label type.