# Changes in version 2017.2.0

UFL 2017.2.0 was released on 2017-12-05.

## Summary of changes

- Add `CellDiameter` expression giving diameter of a cell, i.e., maximal distance between any two points of the cell. Implemented for all simplices and quads/hexes.

- Make `(Min|Max)(Cell|Facet)EdgeLength` working for quads/hexes

## Detailed changes

- Add geometric quantity `CellDiameter` defined as a set diameter of the cell, i.e., maximal distance between any two points of the cell; implemented on simplices and quads/hexes

- Rename internally used reference quantities `(Cell|Facet)EdgeVectors` to `Reference(Cell|Facet)EdgeVectors`

- Add internally used quantites `CellVertices`, `(Cell|Facet)EdgeVectors` which are physical-coordinates-valued; will be useful for further geometry lowering implementations for quads/hexes

- Implement geometry lowering of `(Min|Max)(Cell|Facet)EdgeLength` for quads and hexes