From 21.04 to 21.10 Development Release

[neblaz]

I have 21.04.
sudo do-release-upgrade -d
Checking for a new Ubuntu release
Upgrades to the development release are only
available from the latest supported release.

When will be the next Development Release 21.10 available?

[KGIII]

If you don’t mind installing from an .iso, there have been daily Impish builds for a little while already.

http://iso.qa.ubuntu.com/qatracker/milestones/424/builds

I assume you know the risks of running a very early build.

[neblaz]

I’ll wait for

sudo do-release-upgrade -d

From 20.10 to 21.04 I also changed early, but via command line.
It worked the whole time very well.

[guiverc]

The opening of impish felt late to me… but there have been problems with many builds with a clogged build queue…

(eg. with my Ubuntu News hat on I’m still waiting to post the closing of xenial repositories & Ubuntu 16.04 end of standard support which was scheduled for 29-April-2021… The Ubuntu Release Team are however waiting for arm64 builds of grub+shim to complete before they did this… thus we’re waiting… FYI: Some issues have been reported publically)

Without the -d option the do-release-upgrade checks with https://changelogs.ubuntu.com/meta-release for what is available, however with -d the command instead uses the file https://changelogs.ubuntu.com/meta-release-development where you’ll note impish isn’t there yet… thus why your attempted upgrades aren’t currently working…

FYI:

If I

guiverc@d960-ubu2:/de2900/lubuntu_64$   cat /etc/os-release 
PRETTY_NAME="Ubuntu Impish Indri (development branch)"
NAME="Ubuntu"
VERSION_ID="21.10"
VERSION="21.04 (Impish Indri)"

you’ll note a really petty bug in a missed 21.04, it was reported, fix committed but still hasn’t built…

Patience maybe required (be it hours, or days…), just as I’m still waiting to post the last Xenial notice to Ubuntu News (ETA for that notice is still 30-April-2021 )