# Archived enhancement proposals

This is where enhancement proposals go once they are final, rejected, withdrawn or
superseded. A final OEP is the record of how its functionality was proposed, built and
verified. It is not updated to follow later changes, which the manual describes
([OEP 0](../oep-0000-process.md) §6).

```{toctree}
:maxdepth: 1

oep-0001-propagation-interface
oep-0002-compact-infrared
oep-0003-infrared-windows
oep-0004-mixture-index
oep-0005-hyperpolarizability-support
oep-0006-two-photon-ionisation
```