[Agda] [ANNOUNCE] Agda 2.6.4 released!

[Andreas Abel]

Dear all,

The Agda Team is very pleased to announce the release of Agda 2.6.4.
(Finally, phew, after 3 RCs!)

Thanks to everyone who gave us feedback on the release candidates!

# Highlights of Agda 2.6.4

* Cubical Agda now displays boundary conditions in interactive mode
      (PR [#6529](https://github.com/agda/agda/pull/6529)).

* An inconsistency in the treatment of large indices has been fixed
      (Issue [#6654](https://github.com/agda/agda/issues/6654)).

* Unfolding of definitions can now be fine-controlled via `opaque` 
definitions.

* Additions to the sort system: `LevelUniv` and `Propω`.

* New flag `--erasure` with several improvements to erasure (declared 
run-time irrelevance).

* New reflection primitives for meta-programming.

# GHC supported versions

Agda 2.6.4 has been tested with GHC 9.6.3, 9.4.7, 9.2.8, 9.0.2, 8.10.7, 
8.8.4 and 8.6.5 on Linux, macOS and Windows.

# Installation

Agda 2.6.4 can be installed using cabal-install or stack:

1. Getting the tarball

        $ cabal update
        $ cabal get Agda-2.6.4
        $ cd Agda-2.6.4

2. a. Using cabal-install

        $ cabal install -f +optimise-heavily -f +enable-cluster-counting

2. b. Using stack

        $ stack --stack-yaml stack-a.b.c.yaml install --flag 
Agda:optimise-heavily --flag Agda:enable-cluster-counting

replacing `a.b.c` with your version of GHC.

The flags mean:

    - optimise-heavily:
      Turn on extra optimisation for a faster Agda.
      Takes large resources during compilation of Agda.

    - enable-cluster-counting:
      Enable unicode clusters for alignment in the LaTeX backend.
      Requires the ICU lib to be installed and known to pkg-config.

These flags can be dropped from the install if causing trouble.

# Standard library

You can use standard library v1.7.2 or the `master` branch of the
standard library with Agda 2.6.4.  This branch is available at

        https://github.com/agda/agda-stdlib/

# Fixed issues over Agda 2.6.3

  https://hackage.haskell.org/package/Agda-2.6.4/changelog


Enjoy Agda!

Andreas, on behalf of the Agda Team