Mines running.
[ricklinux@eos-plasma ~]$ balooctl status
Baloo File Indexer is running
Indexer state: Idle
Total files indexed: 83
Files waiting for content indexing: 0
Files failed to index: 0
Current size of index is 416.00 KiB
[ricklinux@eos-plasma ~]$
I had no issues with baloo since last year…
❯ balooctl status
Baloo File Indexer is running
Indexer state: Idle
Total files indexed: 8,000
Files waiting for content indexing: 0
Files failed to index: 0
Current size of index is 133.12 MiB
For these errors …
kwin_xkbcommon: XKB: Couldn't process include statement for ...
https://bbs.archlinux.org/viewtopic.php?id=263764
~/.config/kxkbrc
...
VariantList=basic
Just be aware that Plasma might clobber this setting after manual change.
I found the padding changes in 5.21 (and collapsed padding for menu separators) jarring in context menus. I took a different approach by rebuilding the breeze package locally and changing the variables in build():
sed -i 's/MenuItem_SeparatorPadding = 0/MenuItem_SeparatorPadding = 3/g' $pkgname-$pkgver/kstyle/breezemetrics.h
sed -i 's/MenuItem_MarginWidth = 8/MenuItem_MarginWidth = 5/g' $pkgname-$pkgver/kstyle/breezemetrics.h
sed -i 's/MenuItem_MarginHeight = 4/MenuItem_MarginHeight = 3/g' $pkgname-$pkgver/kstyle/breezemetrics.h
(Left: Stock | Right: Patched)
Not sure if it’s my system or breeze-gtk, but Firefox and Thunderbird had some really huge paddings on the menu bar, I just downgraded breeze-gtk=5.20 for the time being.
Other then that, it’s been a smooth update (literally - the KWin optimisations are really nice!)
Hi,
I just installed KDE Plasma on one of my machines as a gnome replacement and I really feel like my machine is more responsive. Congratulations to the KDE developers, they do a great job!
Translated with https://www.deepl.com/translator
Just got another raft of KDE updates.
Are you on KDE-unstable, there seems to be a qt6 beta! 
Nope… 
Edit: You try?
Haven’t shown up on my mirrors yet. I’ll give it a try for the lulz, but expect a hard rollback.
There it is, KDE apps 20.12.3 just dropped here too.
The QT6 packages should be in KDE-unstable(?) since the 2nd, but they aren’t picked up here, which seems unusual. KDE-unstable is enabled in /etc/pacman.conf. 
I assume because the whole plasma desktop is still build and depending on QT5 there’s no chance to pick them up without forgoing plasma - which isn’t a viable option.