update release notes

RELEASE_NOTES.rst

@@ -6,25 +6,60 @@ Release notes
 ARTIQ-5
 -------
 
-* The :class:`~artiq.coredevice.ad9910.AD9910` and
-  :class:`~artiq.coredevice.ad9914.AD9914` phase reference timestamp parameters
-  have been renamed to ``ref_time_mu`` for consistency, as they are in machine
-  units.
-* :func:`~artiq.tools.verbosity_args` has been renamed to
-  :func:`~artiq.tools.add_common_args`, and now adds a ``--version`` flag.
+Highlights:
+
+* Performance improvements:
+  - Faster RTIO event submission (1.5x improvement in pulse rate test)
+    See: https://github.com/m-labs/artiq/issues/636
+  - Faster compilation times (3 seconds saved on kernel compilation time on a typical
+    medium-size experiment)
+    See: https://github.com/m-labs/artiq/commit/611bcc4db4ed604a32d9678623617cd50e968cbf
+* Improved packaging and build system:
+  - new continuous integration/delivery infrastructure based on Nix and Hydra,
+    providing reproducibility, speed and independence.
+  - rolling release process (https://github.com/m-labs/artiq/issues/1326).
+  - firmware, gateware and device database templates are automatically built for all
+    supported Kasli variants.
+  - new JSON description format for generic Kasli systems.
+  - Nix packages are now supported.
+  - many Conda problems worked around.
+  - controllers are now out-of-tree.
+  - split packages that enable lightweight applications that communicate with ARTIQ,
+    e.g. controllers running on non-x86 single-board computers.
+* Improved Urukul support:
+  - AD9910 RAM mode.
+  - Configurable refclk divider and PLL bypass.
+  - More reliable phase synchronization at high sample rates.
+  - Synchronization calibration data can be read from EEPROM.
 * A gateware-level input edge counter has been added, which offers higher
   throughput and increased flexibility over the usual TTL input PHYs where
   edge timestamps are not required. See :mod:`artiq.coredevice.edge_counter` for
   the core device driver and :mod:`artiq.gateware.rtio.phy.edge_counter`/
   :meth:`artiq.gateware.eem.DIO.add_std` for the gateware components.
+* With DRTIO, Siphaser uses a better calibration mechanism.
+  See: https://github.com/m-labs/artiq/commit/cc58318500ecfa537abf24127f2c22e8fe66e0f8
+* Schedule updates can be sent to influxdb (artiq_influxdb_schedule).
+* Experiments can now programatically set their default pipeline, priority, and flush flag.
 * List datasets can now be efficiently appended to from experiments using
   :meth:`artiq.language.environment.HasEnvironment.append_to_dataset`.
+* The core device now supports IPv6.
+* To make development easier, the bootloader can receive firmware and secondary FPGA
+  gateware from the network.
+* Python 3.7 compatibility (Nix and source builds only, no Conda).
+* Various other bugs from 4.0 fixed.
+* Preliminary Sayma v2 and Metlino hardware support.
+
+Breaking changes:
+
+* The :class:`~artiq.coredevice.ad9910.AD9910` and
+  :class:`~artiq.coredevice.ad9914.AD9914` phase reference timestamp parameters
+  have been renamed to ``ref_time_mu`` for consistency, as they are in machine
+  units.
 * The controller manager now ignores device database entries without the
-  ``"command"`` key set to facilitate sharing of devices between multiple
+  ``command`` key set to facilitate sharing of devices between multiple
   masters.
 * The meaning of the ``-d/--dir`` and ``--srcbuild`` options of ``artiq_flash``
   has changed.
-* Experiments can now programatically set their default pipeline, priority, and flush flag.
 * Controllers for third-party devices are now out-of-tree.
 * ``aqctl_corelog`` now filters log messages below the ``WARNING`` level by default.
   This behavior can be changed using the ``-v`` and ``-q`` options like the other