Official announcement can be found here:
https://solus-project.com/2017/08/15/solus-3-released/

Text of the announcement reproduced below: 
Budgie 10.4 now has maximize and unmaximize animations for applications.

In this release of Budgie, the alt+tab switcher will now prefer the theme
icon instead of the X11 icon where possible. Shift+Alt+Tab support has
also been implemented, enabling you to go backwards in the Alt+Tab dialog.

This release introduces a new applet, Night Light, which can help reduce
eye strain by reducing your display’s blue light by making your screen
“warmer”. This applet integrates into the Night Light functionality
provided in Mutter 3.24.x and provides quick access to toggling Night
Light on/off, as well as:

-Changing the schedule between “Sunset to Sunrise” and “Manual” (which is
configured in GNOME Control Center)
-Temperature of the display when enabled
-One-click access to launch your Display settings

The Places Indicator applet also received some love this release, with a
new option to always expand the places section when the applet is shown.
The whole Places section header is now a clickable button, making
toggling the section easier. The Places Applet icon has also been
changed to a more apt folder icon, better representing “places” rather
than “disks” as previously presented.


The Calendar widget in Raven will now remove the date selection if you
change the month or year.
The Icon Tasklist applet no longer has a list of “derper” applications
for which we’d override the icon. If a .desktop file is found, use the
icon referenced in it.
The User Indicator now has updated and refined iconography thanks to Sam Hewitt.

Budgie Menu

Building upon the lessons learned when (and inspiration from) implementing
the Brisk Menu for MATE, searching has been completely overhauled. We now
support the use of categories for searching and provide a predictable, sane
search mechanism. Items that previously would not show up as expected, such
as searching for “Displays”, are now resolved.

For items that would show up in excess, we now de-duplicate search results
to only showing unique entries when we’re in “search mode” or “super compact”
mode (in other words, no headers or sidebar categories).

We now dynamically compute scores for a given entry during search in relation
to the search term. Assuming the entry is relevant, we’ll display results
in a given order and allow terms to match and display higher up in the list
depending on how close it is to the term, the contents, how much a string
is matched, etc.

Panels

Vertical Panels

In Budgie 10.4, you can now set vertical panels on the left and right sides
of your display. Popovers will correctly indicate (with its “tail”) the
point of origin, we’ve done extensive work to ensure all of our animations
and applets will display and adjust depending on if they are on
(or originating from) a horizontal or vertical panel, and Raven will account
for right-side panels and slide out from underneath the panel, as well as
anchor to left panels when no horizontal or right panel exists.

Transparency

With these new panels, you will now also be able to control the panel
transparency (via our new Settings app) with three modes:

-None: The panel is always opaque.
-Dynamic: The panel is opaque when there is a maximized window on the workspace, or Raven is open, otherwise it’s transparent.
-Always: The panel is always transparent.

Docks

As if Budgie panels couldn’t improve more, we’ve also introduced a Dock
mode for panels, enabling you to put a dock on any side of your display!

This Dock mode also uses a custom CSS class, which means theme developers
have the ability to implement custom styling.

Popovers

For Budgie 10.4, we implemented the Budgie.Popover widget, enabling us to
replace our usage of Gtk.Popover and fix a long-standing issue with
inconsistent popover animations, for example Budgie Menu animating across
the screen if the user’s panel (and the menu applet) was at the bottom.

Furthermore, this Popover widget enables more granular positioning
regardless of its origin (top, bottom, left, or right). This granular
positioning helped to provide us the opportunity to implement panels for
all sides of your display!

Settings

Budgie 10.4 moves Settings out of Raven and into a dedicated application.
This new Budgie Settings application enables us to improve the user
experience of managing panels, applets, and their respective settings,
as well as providing us the opportunity to describe what particular
settings may do, with the classic example being “Disable unredirection
of windows”. To open Budgie Settings, the behavior of the Settings button
at the bottom of Raven has been changed to open Budgie Settings instead
of GNOME Control Center. You can also pin our Settings application to 
your panel, like you would any application, and launch it via Budgie Menu.

n the image above, you can see the management of the Bottom Panel. We
have split panel management into two sections, with Applets being the
primary section (as we anticipate users primarily making changes to
applets) and Settings. Similar to the behavior of prior Budgie releases,
you can move applets around using the up or down arrow buttons, or delete
them. These buttons are positioned at the top of the list to make them
more easily accessible for lower-resolution displays.

To the right of the applet list, you have a dedicated “Add applet” button
and settings for the selected applet below.

In the Settings section of a panel, a multitude of options are exposed, such as:

-Position of the panel
-Size of the panel (height for vertical panels, width for horizontal panels)
-Auto-hide settings (including Intellihide, which is great for Dock mode)
-Transparency settings (as discussed in the Panels -> Transparency section of
this blog post)
-Shadow (a decorative drop shadow)
-Stylize region
-Dock mode

Budgie Settings also enables you to manage the autostarting of applications,
eliminating the need for a secondary tool such as GNOME Tweak Tool.

Other Fixes and Improvements

In addition to the above mentioned goodies, some other fixes include:

The Clock applet will now only redraw when the label contents would change.
This resolves unnecessary redraws of the applet.
daemon: Fixed the order of left-side window buttons, ensuring that the window
decoration style is consistent between native and CSD window decorations.
wm: Ensuring we purge old backgrounds from the cache.

Copyright © 2015-2017 Solus Project. 
