Canonical has prevented Ubuntu 18.04 LTS (Bionic Beaver) from upgrading to 32-bit Ubuntu 18.10, and today the company again announced that it will not continue to support 32-bit systems since the upcoming Ubuntu 19.10 (Eoan Ermine).
Steve Langasek said in an e-mail: "The Ubuntu engineering team has reviewed many facts and concluded that we should not continue to promote i386 as an architecture. Therefore, i386 will not be included in the 19.10 version of the architecture support list, and we will soon begin to disable it for the Eoan Series in the Ubuntu infrastructure.
Although Canonical says that 32-bit applications will no longer be available in the upcoming Ubuntu system, 32-bit applications can still be run on this Linux-based system if users need to use some applications. Application developers can provide these content to users through supported file formats (perhaps Snap, Flatpak or AppImage).