In a follow-up email to a discussion from May when Ubuntu Desktop team discussed the possibility of removal of the 32-bit (i386) installation images from the servers, developer Dimitri John Ledkov confirmed the decision today.

Long story short, starting with Ubuntu 17.10 (Artful Aardvark), Canonical won't offer ISO images for the i386 architecture for the Server (classic) and Desktop versions, but they will continue to provide security updates for existing 32-bit installations via the main Ubuntu archive, as well as Ubuntu Core, Cloud, Container, NetInst, and Server (subiquity) images.

"Please action the below and remove Ubuntu Desktop i386 daily-live images from the release manifest for Beta and Final milestones of 17.10 and therefore do not ship ubuntu-desktop-i386.iso artifact for 17.10," said Dimitri John Ledkov, Software Engineer at Canonical. "There is no longer any effective qa or testing of the desktop product on actual i386 hardware (explicitly non x86_64 CPUs)."

No official Ubuntu flavor announced deprecation of 32-bit images

At the moment of writing, no official Ubuntu flavor announced that they'd follow suit and drop support for new 32-bit (i386) installations starting with Ubuntu 17.10 (Artful Aardvark), which hits the streets in three weeks, on October 19, 2017. Flavors like Lubuntu and Xubuntu, which are designed for old computers, most probably won't drop 32-bit support anytime soon.

We've talked with Lubuntu contributor and developer Simon Quigley, who told us that Lubuntu would continue to be available for i386 machines. The Ubuntu 17.10 Final Beta (Beta 2 for opt-in flavors) milestone is dropping tomorrow, September 28, but it would appear that Ubuntu itself won't ship with 32-bit ISOs for Desktop and Server, only 64-bit ones. Will keep you posted if that changes!