Hello, I have a new Raspberry Pi 400 running the standard Raspbian OS it comes with. I installed Thunderbird (latest) using Synaptic Package Manager. Thunderbird itself seems OK, but Lightning is missing. I use TB on other computers, and I read that Lightning now comes built-in (according to Debian forum -- RPi OS is based on Debian), but there's no sign of it. Moreover, when I go to Addons and try to load Lightning, the only versions listed are all marked as incompatible with this version of TB. I also went into Synaptic and installed the 'Lightning Transition Package', which appeared to get installed but has not made any difference. So far the Raspberry Pi's forum has been no help, other than to send me here. How the blazes do I install Lightning on a version of TB that is supposed to have it already?? Thanks.