Lubuntu 18.10, our first release with LXQt, has reached End of Life as of July 18, 2019. This means that no further security updates or bugfixes will be released. We highly recommend that you update to 19.04 as soon as possible if you are still running Lubuntu 18.10.
The only currently-supported releases of Lubuntu today are 18.04, with LXDE, and 19.04, with LXQt. All other releases of Lubuntu are considered unsupported, and will not receive any further updates from the Lubuntu team. Please note that the i386 architecture is still supported for 18.04, while 19.04 and beyond do not have support. You can find more details here.
You can find instructions on how to upgrade your Lubuntu installation to a new release here. Upgrading from releases before or including 18.04 to 18.10 or greater is unsupported and will break your system. Please do a fresh install.
More information, including how to install Lubuntu, is available on our Downloads page.