# 2.5. Version 5.16 (2023/09/26)

New Features

  - Add ability to specify arbitrary skinned surfaces that can be used in postprocessing, BCs, etc.

  - Expanded plugin compatibility to include flux BCs, initial conditions, and a few previously missing material properties.

  - Off-diagonal terms are now optional for tensor string functions, consistent with the behavior of other tensor types. If omitted, they default to 0.

  - Added the ability to define and use tensor mobility terms with the chemical potential transport model for species diffusion.

  - Added `all_bulk_elements` alias that can be used for BCs, postprocessors, etc in the same way as all_surfaces and all_blocks.

  - Added the ability to offset DOFs in contact enforcements. This is typically useful in tandem with periodic contact or for cases where a prescribed jump across a contact interface is desired.

Upcoming Deprecations (will warn in 5.16)

  - Coupling with Nalu is deprecated. Switch to Sierra/PMR for MPMD participating media radiation solves.

  - Specifying `skinned_blocks` to automatically create skinned block surfaces is deprecated. Refer to the skinned surfaces section for updated syntax.

New Deprecations (will error in 5.16)

  - The `List Mesh Groups` command has been removed. It has not had any effect for several releases, so no mitigation is needed.

  - The legacy line commands for specifying contact material models have been deprecated in favor of the their generic material syntax equivalents. See Contact Materials for more details on specifying these commands. Note that the deprecation messages should also offer exact conversions to the new syntax.

  - The `Using data specification` command for flux BCs is deprecated - use the required parameters directly.

  - Specifying VOLUME or MASS postprocessors on a surface is deprecated. Switch to AREA if you need the area of a surface.