The core GROMACS team wants to let users and downstream developers know about impending changes so that disruption is minimized. Do get in touch if you feel something inappropriate is planned!

Deprecated functionality often remains in GROMACS for a year or more, but this should not be relied upon.

# Changes anticipated to GROMACS 2020 functionality¶

## gmx mdrun -membed¶

The feature for embedding a protein in a membrane will be retained, but probably in a different form, such as gmx membed.

## gmx mdrun -rerun¶

The feature for computing potential energy quantities from a trajectory will be retained, but probably in a different form, such as gmx rerun and gmx test-particle-insertion.

## Integrator .mdp options will only contain dynamical integrators¶

Energy minimization will be accessed in a differt form, perhaps with gmx minimize and interpret an .mdp field for which minimizer to use. Normal-mode analysis may be accessed with e.g. gmx normal-modes. The command-line help for these tools will then be better able to document which functionality is supported when.

## Much functionality in trjconv, editconf, eneconv and trjcat¶

The functionality in such tools is being separated to make it available in composable modules, that we plan to make available as simpler tools, and eventually via the GROMACS API that is under development.

## gmx do_dssp to be replaced¶

This tool is deprecated, because it is problematic for some users to obtain and install a separate DSSP binary, so we plan to replace the implementation at some point with a native implementation, likely based upon xssp, and make it available under a new gmx tool name.

# Functionality deprecated in GROMACS 2020¶

## Support for 32bit architectures¶

Issue 3252 There are no current or planned large scale resources using 32bit architectures, and we have no ability to properly test and evaluate them.

## Free-energy soft-core power 48¶

Issue 3253 Free-energy soft-core power 48 is almost never used and is therefore deprecated.

## Support for Armv7¶

Issue 2990 There are several issues with current code for the architecture, and we don’t have the resources for support and fix issues related to it. As the architecture has no large HPC impact it is thus deprecated.

# Functionality deprecated in GROMACS 2019¶

## Generation of virtual sites to replace aromatic rings in standard residues¶

Issue 3254 These are thought to produce artefacts under some circumstances (unpublished results), were never well tested, are not widely used, and we need to simplify pdb2gmx.

## Benchmarking options only available with gmx benchmark¶

Issue 3255 Options such as -confout, -resethway, -resetstep are not intended for use by regular mdrun users, so making them only available with a dedicated tool is more clear. Also, this permits us to customize defaults for e.g. writing files at the end of a simulation part in ways that suit the respective mdrun and benchmark use cases, so -confout will no longer be required.

## gmx mdrun -nsteps¶

Issue 3256 The number of simulation steps described by the .tpr file can be changed with gmx convert-tpr, or altered in .mdp file before the call to gmx grompp. The convenience of this mdrun option was outweighted by the doubtful quality of its implementation, no clear record in the log file, and lack of maintenance.