In metric monitors, users can now define segments with a SQL Expression. Previously, segmentation could only be configured by picking 1 or 2 fields.
This helps support a long tail of segmentation use cases. For example, when segmenting, users can now concatenate many different fields (e.g. if you wanted to segment by 4 or 5 different fields), or shorten really long field values that impair usability.
Learn more about segmentation.